Alternator issues 1976 Palm Beach
- Thread starter Sketch4u
- Start date
While you are at it - Mr. ERF has some fantastic tips on his photo site folder http://www.gmcmhphotos.com/photos/g5493-gmc-cranking-improve-for-free.html
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, CA
Howell EFI + EBL + Electronic Distributor
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, CA
Howell EFI + EBL + Electronic Distributor
I did find last night in the fuse panel (glove box), the "Aux. Battery" fuse keeps blowing. I am thinking, I obviously have a short! Could it be from
house battery to front or is it possible the isolator box or solenoid is bad?
Samuel
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach
house battery to front or is it possible the isolator box or solenoid is bad?
Samuel
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach
What part of "deteriorated insulation on a large unfused conductor" does
not cause you cause for concern. Disconnect ALL BATTERIES NOW and replace
that wire before it burns your coach to the lugnuts.
Don't buy any more alternators until you fix this. Please heed my warning
on this. We aren't making any more GMCs.
Jim Hupy
Salem, Oregon
On Sat, Sep 14, 2019, 7:41 AM Samuel Ferguson via Gmclist <
> I did find last night in the fuse panel (glove box), the "Aux. Battery"
> fuse keeps blowing. I am thinking, I obviously have a short! Could it be
> from
> house battery to front or is it possible the isolator box or solenoid is
> bad?
>
> Samuel
>
> --
> Samuel Ferguson
> Pittsfield, Illinois
> (West Central Illinois)
> 1976 GMC Palm Beach
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
not cause you cause for concern. Disconnect ALL BATTERIES NOW and replace
that wire before it burns your coach to the lugnuts.
Don't buy any more alternators until you fix this. Please heed my warning
on this. We aren't making any more GMCs.
Jim Hupy
Salem, Oregon
On Sat, Sep 14, 2019, 7:41 AM Samuel Ferguson via Gmclist <
> I did find last night in the fuse panel (glove box), the "Aux. Battery"
> fuse keeps blowing. I am thinking, I obviously have a short! Could it be
> from
> house battery to front or is it possible the isolator box or solenoid is
> bad?
>
> Samuel
>
> --
> Samuel Ferguson
> Pittsfield, Illinois
> (West Central Illinois)
> 1976 GMC Palm Beach
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
Batteries are not hooked up. As soon as I found the bare wires, overcharging, fuse blowing issues, I unhooked them. I am checking everything with a
meter at this point looking for anything and everything that needs replaced.
Samuel
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
meter at this point looking for anything and everything that needs replaced.
Samuel
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
Sir, if you are replacing the big wire from boost solenoid to generator compartment there is a connector behind the wall in the fuse box cabinet .
You might be able to see it with a good light and a mirror. The connection is an isolated insulated stud fastened to the wall frame. There should be
a good size wire going to it from the 12 volt fuse block. The big wire goes to it then another same wire goes from there to generator compartment.
It is not a one piece wire from front to back. I have never replaced this wire but possibly you could unbolt from stud and hook new wire and pull
thru? I don't know if there are clamps or hangers in between?
--
C. Boyd
76 Crestmont
East Tennessee
You might be able to see it with a good light and a mirror. The connection is an isolated insulated stud fastened to the wall frame. There should be
a good size wire going to it from the 12 volt fuse block. The big wire goes to it then another same wire goes from there to generator compartment.
It is not a one piece wire from front to back. I have never replaced this wire but possibly you could unbolt from stud and hook new wire and pull
thru? I don't know if there are clamps or hangers in between?
--
C. Boyd
76 Crestmont
East Tennessee
I have heard rumors of others fishing a small size water hose over existing wire to insulate it. I have no evidence of this working or not.
> Sir, if you are replacing the big wire from boost solenoid to generator compartment there is a connector behind the wall in the fuse box cabinet
> . You might be able to see it with a good light and a mirror. The connection is an isolated insulated stud fastened to the wall frame. There
> should be a good size wire going to it from the 12 volt fuse block. The big wire goes to it then another same wire goes from there to generator
> compartment. It is not a one piece wire from front to back. I have never replaced this wire but possibly you could unbolt from stud and hook new
> wire and pull thru? I don't know if there are clamps or hangers in between?
--
C. Boyd
76 Crestmont
East Tennessee
> Sir, if you are replacing the big wire from boost solenoid to generator compartment there is a connector behind the wall in the fuse box cabinet
> . You might be able to see it with a good light and a mirror. The connection is an isolated insulated stud fastened to the wall frame. There
> should be a good size wire going to it from the 12 volt fuse block. The big wire goes to it then another same wire goes from there to generator
> compartment. It is not a one piece wire from front to back. I have never replaced this wire but possibly you could unbolt from stud and hook new
> wire and pull thru? I don't know if there are clamps or hangers in between?
--
C. Boyd
76 Crestmont
East Tennessee
Steve,
In no way minimizing the importance of everyone's comments about getting
those wires insulated, but I've seen no reply to your question about the
Aux. Battery fuse. First off, do you have the wiring diagram for your '76
Palm Beach? If not, you need to go to bdub.net or another source and get
it NOW. You might also find it useful, especially in view of the state of
your electrical system, to acquire one of the large copies of the wiring
diagram produced by my son (www.bdub.net/GMC_Motorhome_Wiring_Diagrams.pdf)
(discounted copies of which will be available at GMCMI Mansfield).
More directly to the fuse question: That fuse supplies the solenoid boost
relay on the passenger side firewall. It also feeds the similar relay
located in the rear battery compartment (it bypasses the aux. battery
circuit breaker during boost selection). You should check those relays for
internal and external shorts as the easiest starting point. If you don't
find the problem there, the much more laborious task of finding the shorted
wire becomes necessary. I'd start by disconnecting the relay ends of the
wires and metering the loosened wires with an Ohmmeter (with all battery
and shore power disconnected), following the wiring diagram to know just
what I was checking. It is very unlikely that the house battery or the
isolator is directly responsible for the fuse blowing.
HTH,
Ken H.
On Sat, Sep 14, 2019 at 10:41 AM Samuel Ferguson via Gmclist <
> I did find last night in the fuse panel (glove box), the "Aux. Battery"
> fuse keeps blowing. I am thinking, I obviously have a short! Could it be
> from
> house battery to front or is it possible the isolator box or solenoid is
> bad?
>
> Samuel
>
In no way minimizing the importance of everyone's comments about getting
those wires insulated, but I've seen no reply to your question about the
Aux. Battery fuse. First off, do you have the wiring diagram for your '76
Palm Beach? If not, you need to go to bdub.net or another source and get
it NOW. You might also find it useful, especially in view of the state of
your electrical system, to acquire one of the large copies of the wiring
diagram produced by my son (www.bdub.net/GMC_Motorhome_Wiring_Diagrams.pdf)
(discounted copies of which will be available at GMCMI Mansfield).
More directly to the fuse question: That fuse supplies the solenoid boost
relay on the passenger side firewall. It also feeds the similar relay
located in the rear battery compartment (it bypasses the aux. battery
circuit breaker during boost selection). You should check those relays for
internal and external shorts as the easiest starting point. If you don't
find the problem there, the much more laborious task of finding the shorted
wire becomes necessary. I'd start by disconnecting the relay ends of the
wires and metering the loosened wires with an Ohmmeter (with all battery
and shore power disconnected), following the wiring diagram to know just
what I was checking. It is very unlikely that the house battery or the
isolator is directly responsible for the fuse blowing.
HTH,
Ken H.
On Sat, Sep 14, 2019 at 10:41 AM Samuel Ferguson via Gmclist <
> I did find last night in the fuse panel (glove box), the "Aux. Battery"
> fuse keeps blowing. I am thinking, I obviously have a short! Could it be
> from
> house battery to front or is it possible the isolator box or solenoid is
> bad?
>
> Samuel
>
Silly question - you HAVE proved the isolator has failed using a reliable ohmmeter, have you not? If you have not, do so before replacing it. The
isolater is a low failure item. Simply take the wire(s) off the upper and lower terminals and m,easure the center to each with your ohmmeter. Then
reverse the probes and measure again. You should see low resistance with the probes one way and high the other. This is done with an analog
ohmmeter, or with the diode test setting on adigital meter.
--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
isolater is a low failure item. Simply take the wire(s) off the upper and lower terminals and m,easure the center to each with your ohmmeter. Then
reverse the probes and measure again. You should see low resistance with the probes one way and high the other. This is done with an analog
ohmmeter, or with the diode test setting on adigital meter.
--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
In past posts, I assumed I had issues with an alternator after having to change out on alternator 3 times already, I have traced battery wires from
the front of the coach (engine battery) to the house battery. I have ordered solenoid to replace the solenoid on passenger side engine compartment. I
have ordered an isolator box from NAPA last Friday and it is over a week getting here, to which UPS claims the item possibly got lost or misplaced.
(Imagine that!!)
I am at a loss with the large cable with red coating on it, coming from the left side of the solenoid located on the passenger firewall, next to the
isolator box. The wire is strapped to the frame behind the grill and runs to the driver's side section and then goes into the body of the camper.
(From here, I have no clue) I thought I had found the other end of this cable at the block behind the Converter/Breaker box across from bathroom.
I did remove the Converter box and Breaker Box today and found a "block" that a battery cable wire connects to. With the house battery connected, this
wire has 11.5 -12 volts. I did unhook the wire which appears to be going back to the front of the camper, and while hooked to a battery, it is showing
12 volts. The wire on the block is "zero" I am unsure if the cable I am mentioning is in fact the booster cable...
I do have several decent pictures of the areas I am trying to explain. I must admit when I look at a schematic or any other electrical drawing, it
comes across to me a trying to read Chinese, which I have no clue of. I am more of a type of person, if I can get my hands on it and be able to look
at how it is to go, I can eventually figure it out.
I do apologize for my ignorance and to assure all, I jumped in this purchase of this RV to learn the aspects of how to keep it maintained and serviced
when needed. If and When I get the bugs worked out, it will be going on the road!!! Please forgive me for my ignorance with the above mention, but I
am convinced I will not let this eat my lunch or kick my butt.
I do have a few photos I have taken, but it seems when I try to upload them, I am advised they are too big to send. Another task I am sure I will
eventually figure out.
1976 Palm Beach
Samuel Ferguson
Tele 217-491-2969
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
the front of the coach (engine battery) to the house battery. I have ordered solenoid to replace the solenoid on passenger side engine compartment. I
have ordered an isolator box from NAPA last Friday and it is over a week getting here, to which UPS claims the item possibly got lost or misplaced.
(Imagine that!!)
I am at a loss with the large cable with red coating on it, coming from the left side of the solenoid located on the passenger firewall, next to the
isolator box. The wire is strapped to the frame behind the grill and runs to the driver's side section and then goes into the body of the camper.
(From here, I have no clue) I thought I had found the other end of this cable at the block behind the Converter/Breaker box across from bathroom.
I did remove the Converter box and Breaker Box today and found a "block" that a battery cable wire connects to. With the house battery connected, this
wire has 11.5 -12 volts. I did unhook the wire which appears to be going back to the front of the camper, and while hooked to a battery, it is showing
12 volts. The wire on the block is "zero" I am unsure if the cable I am mentioning is in fact the booster cable...
I do have several decent pictures of the areas I am trying to explain. I must admit when I look at a schematic or any other electrical drawing, it
comes across to me a trying to read Chinese, which I have no clue of. I am more of a type of person, if I can get my hands on it and be able to look
at how it is to go, I can eventually figure it out.
I do apologize for my ignorance and to assure all, I jumped in this purchase of this RV to learn the aspects of how to keep it maintained and serviced
when needed. If and When I get the bugs worked out, it will be going on the road!!! Please forgive me for my ignorance with the above mention, but I
am convinced I will not let this eat my lunch or kick my butt.
I do have a few photos I have taken, but it seems when I try to upload them, I am advised they are too big to send. Another task I am sure I will
eventually figure out.
1976 Palm Beach
Samuel Ferguson
Tele 217-491-2969
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
Samuel,
First off, please quit "throwing parts at" your problem, like a modern,
ill-educated, mechanic. It's very doubtful that all the items you've
mentioned have failed simultaneously and you're just wasting time and money
replacing them without figuring out why. We'll help you learn to diagnose
the individual parts.
Second, learn to post photos. You need to find a program to compress those
from "too big" down to probably 800x600 pixels. There are numerous free
programs available. I use XNView, but the compression routine is a tiny
part of that program, which may not suit your needs. Google something like
"photo compression".
You've pretty much described a standard electrical system -- don't change
anything until you've posted photos to GMCMHPhotos and let us help your
diagnosis.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
www.gmcwipersetc.com
On Fri, Sep 20, 2019 at 9:33 PM Samuel Ferguson via Gmclist <
> In past posts, I assumed I had issues with an alternator after having to
> change out on alternator 3 times already, I have traced battery wires from
> the front of the coach (engine battery) to the house battery. I have
> ordered solenoid to replace the solenoid on passenger side engine
> compartment. I
> have ordered an isolator box from NAPA last Friday and it is over a week
> getting here, to which UPS claims the item possibly got lost or misplaced.
> (Imagine that!!)
> I am at a loss with the large cable with red coating on it, coming from
> the left side of the solenoid located on the passenger firewall, next to the
> isolator box. The wire is strapped to the frame behind the grill and runs
> to the driver's side section and then goes into the body of the camper.
> (From here, I have no clue) I thought I had found the other end of this
> cable at the block behind the Converter/Breaker box across from bathroom.
>
> I did remove the Converter box and Breaker Box today and found a "block"
> that a battery cable wire connects to. With the house battery connected,
> this
> wire has 11.5 -12 volts. I did unhook the wire which appears to be going
> back to the front of the camper, and while hooked to a battery, it is
> showing
> 12 volts. The wire on the block is "zero" I am unsure if the cable I am
> mentioning is in fact the booster cable...
>
> I do have several decent pictures of the areas I am trying to explain. I
> must admit when I look at a schematic or any other electrical drawing, it
> comes across to me a trying to read Chinese, which I have no clue of. I am
> more of a type of person, if I can get my hands on it and be able to look
> at how it is to go, I can eventually figure it out.
>
> I do apologize for my ignorance and to assure all, I jumped in this
> purchase of this RV to learn the aspects of how to keep it maintained and
> serviced
> when needed. If and When I get the bugs worked out, it will be going on
> the road!!! Please forgive me for my ignorance with the above mention, but I
> am convinced I will not let this eat my lunch or kick my butt.
>
> I do have a few photos I have taken, but it seems when I try to upload
> them, I am advised they are too big to send. Another task I am sure I will
> eventually figure out.
>
> 1976 Palm Beach
> Samuel Ferguson
> Tele 217-491-2969
> --
> Samuel Ferguson
> Pittsfield, Illinois
> (West Central Illinois)
> 1976 GMC Palm Beach (A newbie who will not allow this thing to kick my
> butt!!)
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
First off, please quit "throwing parts at" your problem, like a modern,
ill-educated, mechanic. It's very doubtful that all the items you've
mentioned have failed simultaneously and you're just wasting time and money
replacing them without figuring out why. We'll help you learn to diagnose
the individual parts.
Second, learn to post photos. You need to find a program to compress those
from "too big" down to probably 800x600 pixels. There are numerous free
programs available. I use XNView, but the compression routine is a tiny
part of that program, which may not suit your needs. Google something like
"photo compression".
You've pretty much described a standard electrical system -- don't change
anything until you've posted photos to GMCMHPhotos and let us help your
diagnosis.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
www.gmcwipersetc.com
On Fri, Sep 20, 2019 at 9:33 PM Samuel Ferguson via Gmclist <
> In past posts, I assumed I had issues with an alternator after having to
> change out on alternator 3 times already, I have traced battery wires from
> the front of the coach (engine battery) to the house battery. I have
> ordered solenoid to replace the solenoid on passenger side engine
> compartment. I
> have ordered an isolator box from NAPA last Friday and it is over a week
> getting here, to which UPS claims the item possibly got lost or misplaced.
> (Imagine that!!)
> I am at a loss with the large cable with red coating on it, coming from
> the left side of the solenoid located on the passenger firewall, next to the
> isolator box. The wire is strapped to the frame behind the grill and runs
> to the driver's side section and then goes into the body of the camper.
> (From here, I have no clue) I thought I had found the other end of this
> cable at the block behind the Converter/Breaker box across from bathroom.
>
> I did remove the Converter box and Breaker Box today and found a "block"
> that a battery cable wire connects to. With the house battery connected,
> this
> wire has 11.5 -12 volts. I did unhook the wire which appears to be going
> back to the front of the camper, and while hooked to a battery, it is
> showing
> 12 volts. The wire on the block is "zero" I am unsure if the cable I am
> mentioning is in fact the booster cable...
>
> I do have several decent pictures of the areas I am trying to explain. I
> must admit when I look at a schematic or any other electrical drawing, it
> comes across to me a trying to read Chinese, which I have no clue of. I am
> more of a type of person, if I can get my hands on it and be able to look
> at how it is to go, I can eventually figure it out.
>
> I do apologize for my ignorance and to assure all, I jumped in this
> purchase of this RV to learn the aspects of how to keep it maintained and
> serviced
> when needed. If and When I get the bugs worked out, it will be going on
> the road!!! Please forgive me for my ignorance with the above mention, but I
> am convinced I will not let this eat my lunch or kick my butt.
>
> I do have a few photos I have taken, but it seems when I try to upload
> them, I am advised they are too big to send. Another task I am sure I will
> eventually figure out.
>
> 1976 Palm Beach
> Samuel Ferguson
> Tele 217-491-2969
> --
> Samuel Ferguson
> Pittsfield, Illinois
> (West Central Illinois)
> 1976 GMC Palm Beach (A newbie who will not allow this thing to kick my
> butt!!)
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
I have started over and am beginning to weed out the alternator issue.
I have replaced the alternator twice. Prior to replacing the alternator this time, I checked wiring with a digital meter to find out of there were any
shorts.
So far, I have found the booster cable to have coating missing from it where the wore runs on top of the frame behind the grill area. I did check the
wire for any other grounding all the way back to the wiring block (located behind the converter/breaker box) house battery and found no other issues.
I covered the exposed booster cable section with a insulator covering.
Other wiring and items checked (I think is related to the alternator) -
Isolator box - No battery hooked up - Checked the continuity -
"center" lug to "right" lug -I show a 839 reading,
"center lug to "left" lug - showing zero
"left" lug to "right" lug - showing zero
Wiring 1st picture attached:
a red wire from alternator is going to "center" lug. This wire also pigtails and goes to a wire connector connecting to a green wire with a fuse
link, and then goes to the back of the fuse panel box.
Right lug (isolator) - Wire goes to left side of solenoid
Left lug - going to post under "vehicle battery post" sticker.
Solenoid - 2nd picture attached - The way it is wired now.
Left large post - Booster cable, Right post isolator
Left small post - ground
Right small post - wires going towards wiring harness
Right large post - + battery, starter, jumper to "vehicle battery" post
My problem -- When I start the vehicle, I check the output of the alternator on red wire coming from back, and I get 36.9 volts. I am told I should
only see .7 volts.
Any suggestions ????
Samuel
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
I have replaced the alternator twice. Prior to replacing the alternator this time, I checked wiring with a digital meter to find out of there were any
shorts.
So far, I have found the booster cable to have coating missing from it where the wore runs on top of the frame behind the grill area. I did check the
wire for any other grounding all the way back to the wiring block (located behind the converter/breaker box) house battery and found no other issues.
I covered the exposed booster cable section with a insulator covering.
Other wiring and items checked (I think is related to the alternator) -
Isolator box - No battery hooked up - Checked the continuity -
"center" lug to "right" lug -I show a 839 reading,
"center lug to "left" lug - showing zero
"left" lug to "right" lug - showing zero
Wiring 1st picture attached:
a red wire from alternator is going to "center" lug. This wire also pigtails and goes to a wire connector connecting to a green wire with a fuse
link, and then goes to the back of the fuse panel box.
Right lug (isolator) - Wire goes to left side of solenoid
Left lug - going to post under "vehicle battery post" sticker.
Solenoid - 2nd picture attached - The way it is wired now.
Left large post - Booster cable, Right post isolator
Left small post - ground
Right small post - wires going towards wiring harness
Right large post - + battery, starter, jumper to "vehicle battery" post
My problem -- When I start the vehicle, I check the output of the alternator on red wire coming from back, and I get 36.9 volts. I am told I should
only see .7 volts.
Any suggestions ????
Samuel
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
Samuel, Stop, and take a deep breath. Clear you mind, and consider ONLY one
problem at a time.
Let's consider ONLY the alternator and isolator. The isolator is a
DEAD SIMPLE DEVICE. It works electrically in much the same way that a flow
check valve works in a plumbing system. IT ONLY ALLOWS ELECTRICITY TO FLOW
IN ONE DIRECTION.
There is a large conductor, it is supposed to be red in color, that
comes DIRECTLY FROM the output lug on the alternator and ONLY GOES to the
CENTER TAP on the isolator.
WITH THE ENGINE RUNNING, THE VOLTAGE THAT YOU READ ON THE OUTPUT LUG
of the alternator should be exactly the same amount as the voltage that you
read between the isolator CENTER TAP and a good ground point. If it does
not, something is bad in that circuit.
The other TWO LUGS, upper and lower, should read that voltage, MINUS
.7 volts. If either of them does not, REPLACE THE ISOLATOR. It is bad.
Then, you can start tracing the electron flow from there.
Jim Hupy
Salem, Oregon
On Sat, Sep 21, 2019, 11:51 AM Samuel Ferguson via Gmclist <
> I have started over and am beginning to weed out the alternator issue.
>
> I have replaced the alternator twice. Prior to replacing the alternator
> this time, I checked wiring with a digital meter to find out of there were
> any
> shorts.
>
> So far, I have found the booster cable to have coating missing from it
> where the wore runs on top of the frame behind the grill area. I did check
> the
> wire for any other grounding all the way back to the wiring block (located
> behind the converter/breaker box) house battery and found no other issues.
> I covered the exposed booster cable section with a insulator covering.
>
> Other wiring and items checked (I think is related to the alternator) -
>
> Isolator box - No battery hooked up - Checked the continuity -
> "center" lug to "right" lug -I show a 839 reading,
>
> "center lug to "left" lug - showing zero
>
> "left" lug to "right" lug - showing zero
>
> Wiring 1st picture attached:
>
> a red wire from alternator is going to "center" lug. This wire also
> pigtails and goes to a wire connector connecting to a green wire with a fuse
> link, and then goes to the back of the fuse panel box.
>
> Right lug (isolator) - Wire goes to left side of solenoid
>
> Left lug - going to post under "vehicle battery post" sticker.
>
> Solenoid - 2nd picture attached - The way it is wired now.
>
> Left large post - Booster cable, Right post isolator
>
> Left small post - ground
>
> Right small post - wires going towards wiring harness
>
> Right large post - + battery, starter, jumper to "vehicle battery" post
>
>
> My problem -- When I start the vehicle, I check the output of the
> alternator on red wire coming from back, and I get 36.9 volts. I am told I
> should
> only see .7 volts.
>
> Any suggestions ????
>
> Samuel
> --
> Samuel Ferguson
> Pittsfield, Illinois
> (West Central Illinois)
> 1976 GMC Palm Beach (A newbie who will not allow this thing to kick my
> butt!!)
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
problem at a time.
Let's consider ONLY the alternator and isolator. The isolator is a
DEAD SIMPLE DEVICE. It works electrically in much the same way that a flow
check valve works in a plumbing system. IT ONLY ALLOWS ELECTRICITY TO FLOW
IN ONE DIRECTION.
There is a large conductor, it is supposed to be red in color, that
comes DIRECTLY FROM the output lug on the alternator and ONLY GOES to the
CENTER TAP on the isolator.
WITH THE ENGINE RUNNING, THE VOLTAGE THAT YOU READ ON THE OUTPUT LUG
of the alternator should be exactly the same amount as the voltage that you
read between the isolator CENTER TAP and a good ground point. If it does
not, something is bad in that circuit.
The other TWO LUGS, upper and lower, should read that voltage, MINUS
.7 volts. If either of them does not, REPLACE THE ISOLATOR. It is bad.
Then, you can start tracing the electron flow from there.
Jim Hupy
Salem, Oregon
On Sat, Sep 21, 2019, 11:51 AM Samuel Ferguson via Gmclist <
> I have started over and am beginning to weed out the alternator issue.
>
> I have replaced the alternator twice. Prior to replacing the alternator
> this time, I checked wiring with a digital meter to find out of there were
> any
> shorts.
>
> So far, I have found the booster cable to have coating missing from it
> where the wore runs on top of the frame behind the grill area. I did check
> the
> wire for any other grounding all the way back to the wiring block (located
> behind the converter/breaker box) house battery and found no other issues.
> I covered the exposed booster cable section with a insulator covering.
>
> Other wiring and items checked (I think is related to the alternator) -
>
> Isolator box - No battery hooked up - Checked the continuity -
> "center" lug to "right" lug -I show a 839 reading,
>
> "center lug to "left" lug - showing zero
>
> "left" lug to "right" lug - showing zero
>
> Wiring 1st picture attached:
>
> a red wire from alternator is going to "center" lug. This wire also
> pigtails and goes to a wire connector connecting to a green wire with a fuse
> link, and then goes to the back of the fuse panel box.
>
> Right lug (isolator) - Wire goes to left side of solenoid
>
> Left lug - going to post under "vehicle battery post" sticker.
>
> Solenoid - 2nd picture attached - The way it is wired now.
>
> Left large post - Booster cable, Right post isolator
>
> Left small post - ground
>
> Right small post - wires going towards wiring harness
>
> Right large post - + battery, starter, jumper to "vehicle battery" post
>
>
> My problem -- When I start the vehicle, I check the output of the
> alternator on red wire coming from back, and I get 36.9 volts. I am told I
> should
> only see .7 volts.
>
> Any suggestions ????
>
> Samuel
> --
> Samuel Ferguson
> Pittsfield, Illinois
> (West Central Illinois)
> 1976 GMC Palm Beach (A newbie who will not allow this thing to kick my
> butt!!)
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
Yes, I have the conductor from alternator - When engine running, I am showing 34. to 36.9 volts from alternator to center lug of isolator.
The same voltage showing to right side of isolator.
No reading showing on left side of isolator.
Samuel
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
The same voltage showing to right side of isolator.
No reading showing on left side of isolator.
Samuel
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
You either have your meter on the wrong scale, you have a faulty meter, OR,
your alternator is running away, ( no regulation) it should be in the range
of 14.5 volts. If it is not your meter setting, then your alternator is
bad. Fix that before you do anything else.
Jim Hupy
Salem, Oregon
On Sat, Sep 21, 2019, 12:45 PM Samuel Ferguson via Gmclist <
> Yes, I have the conductor from alternator - When engine running, I am
> showing 34. to 36.9 volts from alternator to center lug of isolator.
>
> The same voltage showing to right side of isolator.
>
> No reading showing on left side of isolator.
>
> Samuel
>
> --
> Samuel Ferguson
> Pittsfield, Illinois
> (West Central Illinois)
> 1976 GMC Palm Beach (A newbie who will not allow this thing to kick my
> butt!!)
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
your alternator is running away, ( no regulation) it should be in the range
of 14.5 volts. If it is not your meter setting, then your alternator is
bad. Fix that before you do anything else.
Jim Hupy
Salem, Oregon
On Sat, Sep 21, 2019, 12:45 PM Samuel Ferguson via Gmclist <
> Yes, I have the conductor from alternator - When engine running, I am
> showing 34. to 36.9 volts from alternator to center lug of isolator.
>
> The same voltage showing to right side of isolator.
>
> No reading showing on left side of isolator.
>
> Samuel
>
> --
> Samuel Ferguson
> Pittsfield, Illinois
> (West Central Illinois)
> 1976 GMC Palm Beach (A newbie who will not allow this thing to kick my
> butt!!)
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
James,
Can you give me an exact description of what replacement alternator I need. I have been dealing with NAOA here locally and this is the second
alternator I put on in 3 weeks. The 1st one ran about 2 minutes and appeared to be laboring hard and then nothing on output. Both are re-manufactured.
I have read the re-manufactured ones are like flipping a coin as to how long they will work. I think I will skip remanufactured if possible.
I do know NAPA was unable to search by looking up 1976 GMC Palm Beach. One if the guys in parts store mentioned the alternator was the same as fits a
Tornado engine!!! Is this true?
My question is: What info do I input if I were to order online and have shipped to my house. Or is there a parts distributor that you might recommend?
Samuel
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
Can you give me an exact description of what replacement alternator I need. I have been dealing with NAOA here locally and this is the second
alternator I put on in 3 weeks. The 1st one ran about 2 minutes and appeared to be laboring hard and then nothing on output. Both are re-manufactured.
I have read the re-manufactured ones are like flipping a coin as to how long they will work. I think I will skip remanufactured if possible.
I do know NAPA was unable to search by looking up 1976 GMC Palm Beach. One if the guys in parts store mentioned the alternator was the same as fits a
Tornado engine!!! Is this true?
My question is: What info do I input if I were to order online and have shipped to my house. Or is there a parts distributor that you might recommend?
Samuel
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
Sir make sure meter is on DC volts and using red lead to + and black lead to -. Now remove pigtails fuse to fuse box and leave only red wire to
battery isolater and see what you got.
> James,
>
> Brand new digital meter. Meter was set on 20 volts, then I checked it with 200 volts.
>
> Can you give me an exact description of what replacement alternator I need. I have been dealing with NAOA here locally and this is the second
> alternator I put on in 3 weeks. The 1st one ran about 2 minutes and appeared to be laboring hard and then nothing on output. Both are
> re-manufactured. I have read the re-manufactured ones are like flipping a coin as to how long they will work. I think I will skip remanufactured if
> possible.
>
> I do know NAPA was unable to search by looking up 1976 GMC Palm Beach. One if the guys in parts store mentioned the alternator was the same as
> fits a Tornado engine!!! Is this true?
>
> My question is: What info do I input if I were to order online and have shipped to my house. Or is there a parts distributor that you might
> recommend?
>
> Samuel
--
C. Boyd
76 Crestmont
East Tennessee
battery isolater and see what you got.
> James,
>
> Brand new digital meter. Meter was set on 20 volts, then I checked it with 200 volts.
>
> Can you give me an exact description of what replacement alternator I need. I have been dealing with NAOA here locally and this is the second
> alternator I put on in 3 weeks. The 1st one ran about 2 minutes and appeared to be laboring hard and then nothing on output. Both are
> re-manufactured. I have read the re-manufactured ones are like flipping a coin as to how long they will work. I think I will skip remanufactured if
> possible.
>
> I do know NAPA was unable to search by looking up 1976 GMC Palm Beach. One if the guys in parts store mentioned the alternator was the same as
> fits a Tornado engine!!! Is this true?
>
> My question is: What info do I input if I were to order online and have shipped to my house. Or is there a parts distributor that you might
> recommend?
>
> Samuel
--
C. Boyd
76 Crestmont
East Tennessee
> James,
>
> Brand new digital meter. Meter was set on 20 volts, then I checked it with 200 volts.
>
> Can you give me an exact description of what replacement alternator I need. I have been dealing with NAOA here locally and this is the second
> alternator I put on in 3 weeks. The 1st one ran about 2 minutes and appeared to be laboring hard and then nothing on output. Both are
> re-manufactured. I have read the re-manufactured ones are like flipping a coin as to how long they will work. I think I will skip remanufactured if
> possible.
>
> I do know NAPA was unable to search by looking up 1976 GMC Palm Beach. One if the guys in parts store mentioned the alternator was the same as
> fits a Tornado engine!!! Is this true?
>
> My question is: What info do I input if I were to order online and have shipped to my house. Or is there a parts distributor that you might
> recommend?
>
> Samuel
Samuel,
Always us a first default for ordering parts as a {1973, GMC, Transmode, 7.5l} if it is there. For an alternator, a 7(3~6) Toronado with A/C is a
pretty good next choice. (What I think is a great joke about the 73 transmode in most catalogs is that 73 was the year that there were no transmodes.
You cannot buy a real Delco 27SI new, not for years now. Getting a rebuild by a local shop is a better bet than any box job. The problem is that
those shops are a dying breed. I used to work with five different shops. I now have just one. The good guys in there are as old as I am.....
Our Alternators are somewhat special. They are supposed to be "Remote Sensing". This is essential because of the 0.7V drop caused by isolator.
From the post above by several, with the isolator open, the reference voltage back to the alternator is open. That will cause the machine
(alternator) to go to wide open. This can kill them if it is that way at higher than idle speeds.
I hate NAPA's online catalog, it sucks more than a California paper straw.
Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
>
> Brand new digital meter. Meter was set on 20 volts, then I checked it with 200 volts.
>
> Can you give me an exact description of what replacement alternator I need. I have been dealing with NAOA here locally and this is the second
> alternator I put on in 3 weeks. The 1st one ran about 2 minutes and appeared to be laboring hard and then nothing on output. Both are
> re-manufactured. I have read the re-manufactured ones are like flipping a coin as to how long they will work. I think I will skip remanufactured if
> possible.
>
> I do know NAPA was unable to search by looking up 1976 GMC Palm Beach. One if the guys in parts store mentioned the alternator was the same as
> fits a Tornado engine!!! Is this true?
>
> My question is: What info do I input if I were to order online and have shipped to my house. Or is there a parts distributor that you might
> recommend?
>
> Samuel
Samuel,
Always us a first default for ordering parts as a {1973, GMC, Transmode, 7.5l} if it is there. For an alternator, a 7(3~6) Toronado with A/C is a
pretty good next choice. (What I think is a great joke about the 73 transmode in most catalogs is that 73 was the year that there were no transmodes.
You cannot buy a real Delco 27SI new, not for years now. Getting a rebuild by a local shop is a better bet than any box job. The problem is that
those shops are a dying breed. I used to work with five different shops. I now have just one. The good guys in there are as old as I am.....
Our Alternators are somewhat special. They are supposed to be "Remote Sensing". This is essential because of the 0.7V drop caused by isolator.
From the post above by several, with the isolator open, the reference voltage back to the alternator is open. That will cause the machine
(alternator) to go to wide open. This can kill them if it is that way at higher than idle speeds.
I hate NAPA's online catalog, it sucks more than a California paper straw.
Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
63 amp or 100 amp?
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
