Electrical gremlins, charging set up, and questions

A

adam metzger

New member
Oct 12, 2016
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I did some wire tracing this morning with my first cup of coffee.

As far as I can tell, the two batteries in the coach are wired together to the charger. At least, I'm assuming (I know, I know) since one battery's
wires go into a loom and up and over the coach to what looks like the charging area. The other is right there, so that one is easy.

This is the charging situation right now.

http://s66.photobucket.com/user/adammetzger/media/Mobile%20Uploads/2016-09/battery%201%20under%20oven.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/Mobile%20Uploads/2016-09/battery%201%20under%20oven.jpg

battery one inside

http://s66.photobucket.com/user/adammetzger/media/Mobile%20Uploads/2016-09/battery%202%20behind%20fridge.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/Mobile%20Uploads/2016-09/battery%202%20behind%20fridge.jpg

battery two, behind fridge.

http://s66.photobucket.com/user/adammetzger/media/Mobile%20Uploads/2016-09/charger%201.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/Mobile%20Uploads/2016-09/charger%201.jpg

this is the charger being used. Obviously not ideal, but it works.

http://s66.photobucket.com/user/adammetzger/media/Mobile%20Uploads/2016-09/charger%203.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/Mobile%20Uploads/2016-09/charger%203.jpg

.....and this is how it't rigged.

my questions are- where does the house bank normally live, and where do the wires that run from the house system enter the engine compartment? I'm
trying to get back to wiring the isolator.

Does anyone have, or would anyone be willing to-take a picture of their engine compartment and label the items so that I can visualize the set up?

more to this coming soon, and I think I discovered why there were trailer wires wired into the engine compartment.

You guys are gonna love this!!

--
1976 Palm Beach
Austin, TX
 
part two-

http://s66.photobucket.com/user/adammetzger/media/Mobile%20Uploads/2016-11/D284370E-0E16-4B00-B74C-2A63971296F5.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/Mobile%20Uploads/2016-11/D284370E-0E16-4B00-B74C-2A63971296F5.jpg

The unwrapped ball of wonder contained this little gem.

Yes, those are trailer light wires.

http://s66.photobucket.com/user/adammetzger/media/Mobile%20Uploads/2016-11/920DB5D1-DEAC-4264-968E-367467ADAE32.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/Mobile%20Uploads/2016-11/920DB5D1-DEAC-4264-968E-367467ADAE32.jpg

see? I've been wondering what on God's Green Earth was happening here. As I continued my coffee cup probing of the coach, I was looking at Onan's
bedroom and what do you know?

http://s66.photobucket.com/user/adammetzger/media/Mobile%20Uploads/2016-11/67D4D710-5C97-4B51-BE42-E7FAA12A99CB.jpg.html

http://i66.photobucket.com/albums/h252/adammetzger/Mobile%20Uploads/2016-11/67D4D710-5C97-4B51-BE42-E7FAA12A99CB.jpg

another trailer wire adapter wired to the battery bank back here.

Huh.

I think this was so that in case one battery died, it could be jumped by the other!? Does that make sense? would that work? That ball of wonder does
include a wire to the alternator. i believe it also includes a wire to the positive terminal, or the boost switch. (I think it's the boost switch)
maybe both?

What do you think of that??

--
1976 Palm Beach
Austin, TX
 
> part two-
> ...
> What do you think of that??
>

Adam,

I think you need to, right now, disconnect all batteries and external power
sources from that coach.

Next, go here: http://www.bdub.net/GMC_Motorhome_Wiring_Diagrams.pdf to buy
the large-scale chassis wiring diagram for your coach from my son. Then
learn to read it and follow it through your coach, removing all those
about-to-short-and-burn-your-coach electrical MISTAKES. Get it all back to
OEM before you do any "upgrades" -- what you have now are definitely
"downgrades".

Seriously, during the past 65+ years of fooling with automobiles, and a EE
education, I've seldom seen worse wiring than you've shown us -- and you
haven't shown any 120vac circuits yet -- I'm just hoping your PO was afraid
of "high voltage".
I do consider the state of your wiring hazardous.

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc., etc.
www.gmcwipersetc.com
 
Adam,

First, Take KenH's message to heart. From what you have shown the situation you have there is dangerous. Ken does not suggest that you buy the
readable schematic for his son's benefit, but for yours. If you can't read it, find a mentor that can, but do not use that for any excuse to delay
disconnecting what is there.

Second, you asked where the house bank resides in a stock GMC fit 26? It was typically in the space behind the Onan in the rear. I also strongly
suggest that you avoid paralleling 12V batteries. A pair of 6V golf cart batteries will provide much better availability of power.

We are here to help, and you cannot ask stupid questions.

Matt
--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit
 
Is the schematic any different than the one that comes with the cinnabar manuals, other than enlarged?
--
1976 Palm Beach
Austin, TX
 
I own a 1976 Palm Beach.

OEM it came with two batteries in the rear next to the Onan. The connection from the front to the rear batteries was via a 1 ga. cable and through a
50 amp CB. That cable makes a couple of interim stops on the way to the rear batteries. Including the cabinet where the converter is located and a
CB with bypass relay located in the rear.

You really need to get a good copy of the wiring diagram.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
No, Alan's schematic's are merely enlargements of the OEM ones, making them
easily legible. I have the pertinent ones hanging on the inside of my shop
door, held in place, and doubled up so they don't drag, with magnets. I
never try to read the tiny originals.

It's hard to believe the quality of the enlargements from the tiny
originals.

Ken H.

> Is the schematic any different than the one that comes with the cinnabar
> manuals, other than enlarged?
> --
>
 
I also echo Kens comments. That looks to be a potentially dangerous situation.

Batteries should never be hooked up inside the passenger compartment as they off gas hydrogen while charging. One word? Hindenburg.

I can also attest to the usefulness of those wiring diagrams. If any part of it is modified, record it as a separate sub-diagram for future reference.
You can copy that particular section, then white out and note revisions.

At this point probably every GMC out there has had electrical modifications, some beneficial, some dangerous.
--
76 Glenbrook
 
I am no electrical genuis but that is a FUBAR if I ever saw one.

I have the enlarged drawing from Alan Henderson. I drape it over the
bathroom door to roll it out when I have to look at the drawing

On Sun, Nov 6, 2016 at 6:06 AM, Chris Tyler
wrote:

> I also echo Kens comments. That looks to be a potentially dangerous
> situation.
>
> Batteries should never be hooked up inside the passenger compartment as
> they off gas hydrogen while charging. One word? Hindenburg.
>
> I can also attest to the usefulness of those wiring diagrams. If any part
> of it is modified, record it as a separate sub-diagram for future reference.
> You can copy that particular section, then white out and note revisions.
>
> At this point probably every GMC out there has had electrical
> modifications, some beneficial, some dangerous.
> --
> 76 Glenbrook
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
 
Adam,

That is a good start. Save the wire and parts that you take out, the might come in handy.

Before the depression, I did a lot of work on boats. Most were sloops over 30 years old and not retired from racing. I did a lot of this. I often
would take a plastic milk crate aboard empty and take it off full of scrap wire.

I grew to hate two things that you may (Looks like will probably) come to hate as much as I do...
Hidden in-line fuses. (It's dead and you can't figure out why.)
Wires that change description mid-run. (How come the red wire does not go where it should but the blue one does and it should not?)

The only part of a GMC's electrics that should be changed out without it failing is the Buzz-Box (ferro-resonant) converter. Those were the best
available at the time but are so out-classed by the modern smart multi stage that they should be out to pasture.

Matt
--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit
 
Matt-

The sensory feedback in a good wire clip is hard to beat.

Sir, I would absolutely love to sit down and hear about you life and your history. I hope to get the chance some day.
--
1976 Palm Beach
Austin, TX
 
I like to think I'm reasonably astute on Things Electric, so when I got the new to me 26' coach home, step one was removing everything I didn't
want/need in it. Which included a tall dash addendum, and its contents of an alarm clock, indoor outdoor thermometer, audio switches, Ignition and
chassis 12 volt terminal strips, a non-functional TPM, and some other stuff I don't remember. Then I removed the glove box and the knee cover under
the steering wheel which contained 9 add-on switches. The radio/nav system was removed to make room to trace things. The coach fits an external amp,
sub, and speakers with the components under the couch. Wires to these were identified, shortened as required, and labelled. All one - ended wires
were traced back and removed or labelled as required. The switches were traced and labelled, including trans cooler, oil cooler, cruise power, amp
power, sub power, sub panel lights, and a couple of others. Everything was laced up, reconnected, and tested. As a result, I have a cardboard box a
foot cube stuffed with wire and connectors. I've still a bit to go, but reassembly and testing shows it all works. The coach has a second set of
gauges on the knee panel because the PO felt the Mac dash gauges weren't the most accurate. I've a DigiPanel to install which should allow me to
remove several of them.

The point of all this is, when you get a 'hack job', step one is to return it to ground zero. Take out everything which didn't grow in the coach
originally, and rewire it to 'book' spec. Take out ALL the extraneous wires. Make it what it was when GM shipped it, including repairing or
replacing any wires/connectors/components which aren't working. This took me a week and I knew what I was looking for, it may take you longer. Once
you get your coach wiring back to original, there are only two replacements you really should do. Replace the 12 volt fuse panel with a modern
replacement. Replace the 12 volt supply - often called a buzz box - with a more modern 12 volt supply, preferably one with a 'smart' charger for
your house batteries. There are several available.

Now, look at the additional stuff which has grown in the coach that you like. Re-install each, and power it properly from the DC panel using new
wires which are labelled at each end. You can get a P-Touch labeller for about ten dollars if you don't already have one.

The end result of this will be a safer coach with reliable electrics.

As to batteries, my 23' coach has one deep cycle house battery. Since I very seldom dry camp, this is entirely sufficient for my needs. Since it's a
Norris upfit, the batteries are both in front, there's a heavy cable to the genset for cranking power. The coach has a solar array with a smart
charger for the house batteries. It also has a battery disconnect switch in the panel cabinet to disconnect the House battery from the system. As
long as this is used when it's running or powered from shore, there's no need to drop the buzz box. I did so because I needed it elsewhere (it's a
great high current 12 volt bench supply) and I had a 60 Amp supply from one of the suppliers. This system works well, with limited dry camping
capacity.
My 26' came with a pair of deep cycle batteries in the rear compartment behind the Onan and a new 12 Volt supply with smart charger for them. I've
left it alone. It's overkill for my uses but it works well. When the batteries age out, I'll probably replace with a single deep cycle. I've a
source of giant diesel genset batteries, one of which will fill the space now occupied by the two. They're free and two years old, I've used them
often in other services.

The thrust of all this is, get things back to the working stock beginning, discard the dreck, and then refit whatever options you want correctly.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon
 
Let me also note, my 23' has an ammeter for each battery so I can tell what's going on electrically - a voltmeter is a poor substitute. Since wiring
an ammeter to rear house batteries is expensive, my 26' will only get a chassis battery ammeter. I will probably fit one in the rear for the house
batteries, the option being a shunt meter which ain't cheap, or 40 feet of 00/350 cable and ends which is even less cheap and undesirable in the
bargain. The house system really only needs checking when you start out and at the end of the day unless there's a problem.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon
 
Johnny, where did you get your replacement fuse block, what is its name
and part number and how many circuits does it have? Don't want much, do
I? Hope your memory is better than mine.

Thanks,
RonC

On Tue, 08 Nov 2016 08:37:25 -0700 Johnny Bridges via Gmclist

Once you get your coach wiring back to original, there are only two
replacements you really should do. Replace the 12 volt fuse panel
with a modern replacement. Replace the 12 volt supply - often called
a buzz box
- with a more modern 12 volt supply, preferably one with a 'smart'
charger for your house batteries. There are several available.


Ron & Linda Clark
North Plains, ORYGUN
78 Eleganza II
 
Not Johnny but I have purchased and installed two 12v distribution blocks
made by blue sea. I think the total number of fused circuits is around 15
which is more than enough for a typical gmc house panel. The panels come
with labels and a transparent cover. They were around $75 at west marine. I
have been happy with them. It felt good to do away with the melting oem
glass fuse house 12 v panel.

Sully
77 eleganza 2
Seattle

> Johnny, where did you get your replacement fuse block, what is its name
> and part number and how many circuits does it have? Don't want much, do
> I? Hope your memory is better than mine.
>
> Thanks,
> RonC
>
> On Tue, 08 Nov 2016 08:37:25 -0700 Johnny Bridges via Gmclist

>
> Once you get your coach wiring back to original, there are only two
> replacements you really should do. Replace the 12 volt fuse panel
> with a modern replacement. Replace the 12 volt supply - often called
> a buzz box
> - with a more modern 12 volt supply, preferably one with a 'smart'
> charger for your house batteries. There are several available.
>
>
> Ron & Linda Clark
> North Plains, ORYGUN
> 78 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
We are acquiring Digi Devices and should be in production in February.
We have a very qualified Engineer / Technician that will be heading that
department.
This is a very reliable unit with audible warning and shows all the
readings a one time, so one doesn't need to press buttons,
or glance around.
This devise has saved many engines.

On Tue, Nov 8, 2016 at 11:44 AM, David Horowitz
wrote:

> Hi Johnny,
>
> Which "DigiPanel" are you going with? Curious minds want to know...
>
> Thanks,
> Dave
>
> _______________________________________________
> 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
 
Jim,

I, for one, would be willing to pay more for the Digipanel IF the all the inputs were connected with connectors instead of being
hard wired to the unit.

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Jim Kanomata
Sent: Wednesday, November 09, 2016 7:19 AM
To: gmclist
Subject: Re: [GMCnet] Electrical gremlins, charging set up, and questions

We are acquiring Digi Devices and should be in production in February.
We have a very qualified Engineer / Technician that will be heading that department.
This is a very reliable unit with audible warning and shows all the readings a one time, so one doesn't need to press buttons,
or glance around. This devise has saved many engines.

Jim Kanomata
Applied/GMC, Fremont, CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
The DigiPanel came initially from the maker, I got it from the original buyer who never installed it. Kanomata (Applied GMC) has them. You wil hear
the squawk before you see the gauge.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon
 
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