Electrical gremlins, charging set up, and questions

This might help
http://www.gmcmhphotos.com/photos/g5493-gmc-cranking-improve-for-free.html

> This might help
> http://www.gmcmhphotos.com/photos/data/6225/How_to_check-out1.pdf
>
>

>
> I believe the red wire in the loom that you are seeing goes to the fuse
> panel INSIDE the coach. If this is the wire that you are describing, then
> the
> end that you are looking at goes to a large terminal on the blower motor
> relay. From that same blower motor relay terminal there another 6" wire
> that
> goes to the isolator. That wire to the isolator is a 16 ga. fusible link.
>
> I hope I am describing the wire you are asking about.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
 
> I believe the red wire in the loom that you are seeing goes to the fuse panel INSIDE the coach. If this is the wire that you are describing, then
> the end that you are looking at goes to a large terminal on the blower motor relay. From that same blower motor relay terminal there another 6"
> wire that goes to the isolator. That wire to the isolator is a 16 ga. fusible link.
>
> I hope I am describing the wire you are asking about.

Hi Ken-

I have two red wires coming out of the loom...one clearly marked DIODE.

http://s66.photobucket.com/user/adammetzger/media/diode.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/diode.jpg

The pic below shows the same DIODE wire coming off the frame to the right.

http://s66.photobucket.com/user/adammetzger/media/loom%201.jpg.html
http://i66.photobucket.com/albums/h252/adammetzger/loom%201.jpg

I think the wire you are referring to is the one I'm holding in the pic below?

also, am I mistaken that the red wire I'm holding goes to the horn relay, not the blower relay? (I thought the blower relay is the one above it)

http://s66.photobucket.com/user/adammetzger/media/07725f97-0594-4d9c-ba6a-a9956ffbd9c2.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/07725f97-0594-4d9c-ba6a-a9956ffbd9c2.jpg

How is your alternator wire run? Through the loom?
--
1976 Palm Beach
Austin, TX
 
> > I believe the red wire in the loom that you are seeing goes to the fuse panel INSIDE the coach. If this is the wire that you are describing,
> > then the end that you are looking at goes to a large terminal on the blower motor relay. From that same blower motor relay terminal there another
> > 6" wire that goes to the isolator. That wire to the isolator is a 16 ga. fusible link.
> >
> > I hope I am describing the wire you are asking about.
>
>
> hi Ken-
>
> I have two red wires coming out of the loom...one clearly marked DIODE.
>
>
>
> http://i66.photobucket.com/albums/h252/adammetzger/1f9b4fed-99ee-4a94-82c4-e4a65b398bc8.jpg
>
>
> The pic below shows the same DIODE wire coming off the frame to the right.
>
>
>
> http://i66.photobucket.com/albums/h252/adammetzger/bc02e595-607a-4da1-b91f-d1cd83071d78.jpg
>
> I think the wire you are referring to is the one I'm holding in the pic below?
>
> also, am I mistaken that the red wire I'm holding goes to the horn relay, not the blower relay? (I thought the blower relay is the one above it)
>
>
>
> http://i66.photobucket.com/albums/h252/adammetzger/07725f97-0594-4d9c-ba6a-a9956ffbd9c2.jpg
>
> How is your alternator wire run? Through the loom?
>
> also, please notice my beautiful waterproof heat shrink and terminal work.
>
> :)


I believe that the red wire that you are holding is the one that feeds the fuse box inside the coach. That wire in the picture is currently connected
to the correct place on the front of the Blower relay. If I said horn relay in a previous posting then I said it wrong. It should be the blower
relay.

On the picture with the large single terminal with the big 1/2" nut on it, the little black wire going off to the lower right is the fusible link.

I can not give you the correct OEM alternator wire routing from the center terminal of the Isolator by looking at my coach. This is because my coach
had an engine fire 7 years ago. I replaced all of the wiring on the top of the engine at that time. So mine is not stock (OEM).

The GMC wiring diagram says the alternator wire is a red 10 gauge one. I believe the one you are holding is a red 12 gauge one.

Someone else here will have to comment on the wire routing.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
I have posted this several times over the years:

1973 through 1976 models had two relays in that area. The one above the horn is the blower relay for the heater/ air-conditioning blower.
Late 1977 and 1978 models had a third relay at the top which was a delay relay.

The delay relay is the smaller relay at the very top of the panel. It has two leads - on mine they are brown and yellow and one has a male and the other a female terminal at the end of the leads. The leads are approx. 6 to 8 inches long. The female one connects to the male terminal on the lead to the blower motor. The male one leads to the short lead (purple on mine) that goes to the blower relay (terminal 1). If the delay relay burns out you can plug the male motor lead directly into the short female lead going to terminal 1 on the blower relay.

The blower relay (below the delay relay but above the horn relay) has 5 terminals. When the blower relay is mounted with the 5 terminals down, there are two on the left, one in the middle and two on the right.

On the back left side it is #3 which has a red/white wire that leads to a fusible link and that goes into the harness and connects to the red wire from the alternator to the center stud of the battery isolater.

On the front left is terminal #2. Mine has a dark blue wire that leads to the resistor package in the right side of the heater box.

In the center is terminal #1. Mine has a short purple wire with a female connector. The male lead from the delay relay plugs into this (on mine right now I have the blower motor plugged into this as my delay relay is bad and disconnected).

On the right rear is terminal #5. This has a short black lead that goes to a ground screw.

On the right front is terminal #4. This has an orange wire that leads to the heater controls on the dash.

Terminals 4 & 5 control the coil in the blower relay.

Terminals 1 & 2 are normally closed and operate the blower when in low or medium speeds.

Terminal 1 & 3 are normally open but when the dash switch is put in "high" or "max" it actuates the coil and the relay connects these terminals which give power to the blower directly from the alternator in order to get higher voltage and higher blower speed. At the same time it disconnects terminal 2 from the circuit.

Emery Stora
77 Kingsley
Frederick, CO

>
>
> http://i66.photobucket.com/albums/h252/adammetzger/front%202%20notes.jpg
>
> here is a overview pic with notes. according to my schematics, the relay with purple, black, dk blue, orange, and red dbl white wires is the BLOWER
> relay.
>
> Thoughts?
>
> --
> 1976 Palm Beach
> Austin, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
I was hoping that the red wire marked DIODE would be the one to the alt, so I could just attach it to the ALT, and the isolator, then not have to deal
with splitting my new wire.

I guess Im going to have to bust open the loom to dig deeper. I REALLY don't want to do that. literally a tube of worms.
--
1976 Palm Beach
Austin, TX
 
Now I am really confused after Emery's comments any your picture. Please ignore my comments regarding the blower vs. the horn relay. I have to go
look at my coach to figure which one is which and the coach is not at home.

Sorry for the confusion on my part..
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
My morning coffee cup update-

The red DIODE wire is indeed the wire that runs through the loom, across the top of the engine, and to the alternator. it is currently connected to
the other wire running to the relay with the green fusible link correctly. unfortunately, the other end is utter shite. baked hard and covered in
masses of electrical tape.

http://s66.photobucket.com/user/adammetzger/media/engine%20top%201.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/engine%20top%201.jpg

http://s66.photobucket.com/user/adammetzger/media/alt%20wire%201.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/alt%20wire%201.jpg

old fly tying scissors are pretty good for cutting through this crap.
Why would someone double up the wire running from a single wire to a single terminal? Is this a thing?

http://s66.photobucket.com/user/adammetzger/media/engine%20top%202.jpg.html
http://i66.photobucket.com/albums/h252/adammetzger/engine%20top%202.jpg

in unwrapping about 6 feet of old crusty electric tape, I found a suprise. A dk blue wire, cut at both ends, and wrapped up like a mummy. any
ideas? runs to engine compartment, near battery?

BTW, that's the white wire that comes out of the ALT harness.

40 year old white male wire seeks alternator lifestyle for good times. 8)

http://s66.photobucket.com/user/adammetzger/media/alt%20wire%20pigtail.jpg.html

I found a dorman replacement part for this, GMC from 73 to 90 something. the only concern is the wire gauge is smaller on the replacement. any
issues? Should I pull it apart and use new wire correct gauge wire into the new part??

ideas?

Thanks fellas. I was TERRIFIED about the prospect of tearing into engine wiring. but alas, there are really only SO MANY wires, right?

thanks for the encouragement.

--
1976 Palm Beach
Austin, TX
 
You want the right part call us as we stock all.

On Fri, Nov 18, 2016 at 12:01 PM, Adam Metzger
wrote:

> My morning coffee cup update-
>
> The red DIODE wire is indeed the wire that runs through the loom, across
> the top of the engine, and to the alternator. it is currently connected to
> the other wire running to the relay with the green fusible link
> correctly. unfortunately, the other end is utter shite. baked hard and
> covered in
> masses of electrical tape.
>
> http://s66.photobucket.com/user/adammetzger/media/engine%
> 20top%201.jpg.html
>
> http://i66.photobucket.com/albums/h252/adammetzger/engine%20top%201.jpg
>
>
> http://s66.photobucket.com/user/adammetzger/media/alt%20wire%201.jpg.html
>
> http://i66.photobucket.com/albums/h252/adammetzger/alt%20wire%201.jpg
>
> old fly tying scissors are pretty good for cutting through this crap.
> Why would someone double up the wire running from a single wire to a
> single terminal? Is this a thing?
>
> http://s66.photobucket.com/user/adammetzger/media/engine%
> 20top%202.jpg.html
> http://i66.photobucket.com/albums/h252/adammetzger/engine%20top%202.jpg
>
> in unwrapping about 6 feet of old crusty electric tape, I found a
> suprise. A dk blue wire, cut at both ends, and wrapped up like a mummy.
> any
> ideas? runs to engine compartment, near battery?
>
> BTW, that's the white wire that comes out of the ALT harness.
>
> 40 year old white male wire seeks alternator lifestyle for good times. 8)
>
>
> http://s66.photobucket.com/user/adammetzger/media/alt%
> 20wire%20pigtail.jpg.html
>
> I found a dorman replacement part for this, GMC from 73 to 90 something.
> the only concern is the wire gauge is smaller on the replacement. any
> issues? Should I pull it apart and use new wire correct gauge wire into
> the new part??
>
> ideas?
>
> Thanks fellas. I was TERRIFIED about the prospect of tearing into engine
> wiring. but alas, there are really only SO MANY wires, right?
>
> thanks for the encouragement.
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> --
> 1976 Palm Beach
> Austin, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Be are to label EVERY wire you touch

> You want the right part call us as we stock all.
>
>
> On Fri, Nov 18, 2016 at 12:01 PM, Adam Metzger

>
> > My morning coffee cup update-
> >
> > The red DIODE wire is indeed the wire that runs through the loom, across
> > the top of the engine, and to the alternator. it is currently connected
> to
> > the other wire running to the relay with the green fusible link
> > correctly. unfortunately, the other end is utter shite. baked hard and
> > covered in
> > masses of electrical tape.
> >
> > http://s66.photobucket.com/user/adammetzger/media/engine%
> > 20top%201.jpg.html
> >
> > http://i66.photobucket.com/albums/h252/adammetzger/engine%20top%201.jpg
> >
> >
> >
> http://s66.photobucket.com/user/adammetzger/media/alt%20wire%201.jpg.html
> >
> > http://i66.photobucket.com/albums/h252/adammetzger/alt%20wire%201.jpg
> >
> > old fly tying scissors are pretty good for cutting through this crap.
> > Why would someone double up the wire running from a single wire to a
> > single terminal? Is this a thing?
> >
> > http://s66.photobucket.com/user/adammetzger/media/engine%
> > 20top%202.jpg.html
> > http://i66.photobucket.com/albums/h252/adammetzger/engine%20top%202.jpg
> >
> > in unwrapping about 6 feet of old crusty electric tape, I found a
> > suprise. A dk blue wire, cut at both ends, and wrapped up like a mummy.
> > any
> > ideas? runs to engine compartment, near battery?
> >
> > BTW, that's the white wire that comes out of the ALT harness.
> >
> > 40 year old white male wire seeks alternator lifestyle for good times.
> 8)
> >
> >
> > http://s66.photobucket.com/user/adammetzger/media/alt%
> > 20wire%20pigtail.jpg.html
> >
> > I found a dorman replacement part for this, GMC from 73 to 90 something.
> > the only concern is the wire gauge is smaller on the replacement. any
> > issues? Should I pull it apart and use new wire correct gauge wire into
> > the new part??
> >
> > ideas?
> >
> > Thanks fellas. I was TERRIFIED about the prospect of tearing into engine
> > wiring. but alas, there are really only SO MANY wires, right?
> >
> > thanks for the encouragement.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > --
> > 1976 Palm Beach
> > Austin, TX
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Fremont,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
You need to closely look at the wiring diagram. That circuit forred wire that you chased down onthe horn relay terminal goes 3 places and is a 12 ga
wire.
1. To the inside fuse box
2. To ignition switch
3. To the white wire on the alternator plug.

The white wire on the alternator plug is a remote voltage sensing line for the alternator. It moves very little current. I believe the only reason
GM used 12 ga. there was because the white wire was meeting other 12 ga. wires that do carry most of the current (other than the starter) used in the
engine side of the coach.

That white wire going to the alternator plug is NOT the wire carrying the current generated by the alternator and supplied to the center terminal of
the isolator.

The wire carrying alternator power to the isolator center terminal is a heavier 10 ga. RED one. It has single ring terminal on it and it is mounted
on a stud on the back side of the alternator.

I have no idea what this PO was trying to do here.

I am suggesting that you leave that white wire circuit and red wire at the horn relay wire alone for now. You can go back and clean it up later.

On you original problem, You need to find the 10 ga. wire connected on the single terminal on the back of the alternator and chase it down. It is
the one supplying ALL charging power to the Isolator and the coach and should be mounted to the center terminal of the isolator.

I'll repeat. The white wire in the alternator plug is a voltage sense line only.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Hi Ken-

Thanks for your input. I understand that the red wire is the power wire, and it runs from the ALT to the isolator. My PO had run a different
alternator wire, but had it tied into a bunch of superfluous connections as well. This is all an attempt to clean up the more offensive wiring
practices.

in tracing the coaches original red wire, I found the white and brown ALT wires also in poor health. I have clipped the original pigtail, and am
replacing it, and will clean up the connections with either crimps, or solder, and shrinkwrap.

I have run a NEW wire to ALT to the positive junction, as that is how PO had it. I'm trying to get the wiring straight so I can incorporate the
isolator, and in the meantime replace any major wiring issues that may cause me harm down the road.

I'm confused by "circuit forred" that you typed. I think this is a mis type, but cannot reason out what you meant. Sorry If I'm being dense.
--
1976 Palm Beach
Austin, TX
 
Be sure to plug in an APC wire into your alternator for protection
Click on my tag line for more info

> Hi Ken-
>
> Thanks for your input. I understand that the red wire is the power wire,
> and it runs from the ALT to the isolator. My PO had run a different
> alternator wire, but had it tied into a bunch of superfluous connections
> as well. This is all an attempt to clean up the more offensive wiring
> practices.
>
> in tracing the coaches original red wire, I found the white and brown ALT
> wires also in poor health. I have clipped the original pigtail, and am
> replacing it, and will clean up the connections with either crimps, or
> solder, and shrinkwrap.
>
> I have run a NEW wire to ALT to the positive junction, as that is how PO
> had it. I'm trying to get the wiring straight so I can incorporate the
> isolator, and in the meantime replace any major wiring issues that may
> cause me harm down the road.
>
> I'm confused by "circuit forred" that you typed. I think this is a mis
> type, but cannot reason out what you meant. Sorry If I'm being dense.
> --
> 1976 Palm Beach
> Austin, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Read here
http://bdub.net/gmcmotorhome.info/APC.html

> Be sure to plug in an APC wire into your alternator for protection
> Click on my tag line for more info
>
>
> On Sat, Nov 19, 2016 at 9:21 AM Adam Metzger

>
> Hi Ken-
>
> Thanks for your input. I understand that the red wire is the power wire,
> and it runs from the ALT to the isolator. My PO had run a different
> alternator wire, but had it tied into a bunch of superfluous connections
> as well. This is all an attempt to clean up the more offensive wiring
> practices.
>
> in tracing the coaches original red wire, I found the white and brown ALT
> wires also in poor health. I have clipped the original pigtail, and am
> replacing it, and will clean up the connections with either crimps, or
> solder, and shrinkwrap.
>
> I have run a NEW wire to ALT to the positive junction, as that is how PO
> had it. I'm trying to get the wiring straight so I can incorporate the
> isolator, and in the meantime replace any major wiring issues that may
> cause me harm down the road.
>
> I'm confused by "circuit forred" that you typed. I think this is a mis
> type, but cannot reason out what you meant. Sorry If I'm being dense.
> --
> 1976 Palm Beach
> Austin, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
 
OK, on the confusion. I am a terrible typist and I always have to re-read and correct my postings before pressing send. I still miss some errors as
you have seen. I corrected / updated that posting. Let's see if it is understandable now.

http://gmc.mybirdfeeder.net/GMCforum/index.php?t=tree&goto=310594&rid=12

I think we are on the the same page here on the white wire at the alternator. I thought you were chasing the lead to the isolator and had it confused
with the white voltage sense wire. I now see that I was mistaken.

BTW,
If I do not state something clearly, feel free to ask again. If I make a mistake like I did with the blower and horn relays earlier in this thread,
please correct it. You will not hurt my feelings.

If you want to talk about this on the phone, feel free to look up my unlisted home phone number on the GMC BLACK LIST. If you get voice mail and
decide to leave a message, please speak slowly and repeat any numbers twice.


--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
> OK, on the confusion. I am a terrible typist and I always have to re-read and correct my postings before pressing send. I still miss some errors
> as you have seen. I corrected / updated that posting. Let's see if it is understandable now.
>
> http://gmc.mybirdfeeder.net/GMCforum/index.php?t=tree&goto=310594&rid=12
>
> I think we are on the the same page here on the white wire at the alternator. I thought you were chasing the lead to the isolator and had it
> confused with the white voltage sense wire. I now see that I was mistaken.
>
> BTW,
> If I do not state something clearly, feel free to ask again. If I make a mistake like I did with the blower and horn relays earlier in this
> thread, please correct it. You will not hurt my feelings.
>
> If you want to talk about this on the phone, feel free to look up my unlisted home phone number on the GMC BLACK LIST. If you get voice mail and
> decide to leave a message, please speak slowly and repeat any numbers twice.

Thanks Ken! any input on replacing part of a wire vs the entire thing? Id like to replace all three alt wires at least to the other side of the
engine bay, as they're all pretty crusty. My concern is that if I take em all the way back to the OEM wiring splices, I'm going to get the bug to
replace all of them. I found a replacement ALT harness with the correct wire sizing, and I have to replace some of the wire as the new pigtail is too
short.

--
1976 Palm Beach
Austin, TX
 
First get an APC (Alternator Protection Cable) from Gene Fischer and add it to the alternator end of your new cable. You really should have one
plugged on to that cable anyway and it will add 6" to the cable length.

You can get just the connector without the wires already crimped on it. I had an extra one around here but I can not find it. I'll keep looking for
it. Gene Fischer might have one as he uses them to make the APC's.

I'm headed out the door right now so I'll respond some more to the rest of your posting when I return.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
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