Hi Folks
Earlier this week we brought home a 1976 GMC 26' motorhome. I don't even know what model it is as it had an extensive rebuild about 24 years ago. I've been keeping my eyes open for them for a while, this is the 3rd one I've looked at and the first one I seriously considered buying, which we did after a bit of spousal discussion. (she's all in)

It needs CV boot covers and a couple of water leaks fixed, brakes either needed adjusting or bleeding, had to push pretty hard. I'm sure I'll find more mechanical issues, hopefully nothing crazy.
Anyhow, I took a chance and drove it home under it's own power and made it the 150km or so with no drama. It was rarely used after the rebuild and not at all in at least the last 12 years or so but the elderly owner had the wheels, tires, one airbag, brake master cylinder, brake lines and rear brakes replaced, they're all new.

We both recently retired earlyish and want to explore Canada to start and the US eventually with it and our dogs (shelties). We're based out of the Kingston, Ontario area, but I have roots in NB and that would be our first trip with it. We have no previous experience RV'ing.

I've been reading some of the forum and glad I found it. I'm sure I'll have lots of questions.

Burl

Thanks guys. Right now my ambition is to get it into my backyard. I had to trim trees and now I'm trying to get some gravel put down, but I think landscapers might be part of "The Covid Shutdown" here in Ontario, nobody is answering their phones. GMC is sitting in the church parking lot next door which nobody is using.

I've already been searching through the archives for information, but, things change over the years and sometimes new products or methods come up, so I'll still post questions when need be.

I think a lot of stuff isn't "stock" on my machine, especially electrical. Good think I have 30+ years experience figuring out new machinery using vague drawings and prints.

Burl,

You're partially right with "...some of this is not stock." -- Almost NONE
of it is stock! It all appears to be of good quality and well done,
however. I think I can identify some of it for you, 'though the specific
equipment is new to me:

On your first photo (under the right (passenger)side hood, the two relays
to the left (looking in) of the fiberglass heating duct, are the shutoff
relays for the chassis and house batteries. They're controlled by the wall
panel (labelled "Battery Disconnect") in your last photo. The device
labelled "Bidirectional Isolator Delay Relay" is apparently what we
generally call a "Combiner" (as I discussed here a couple of days ago).
This one is unusual in that it apparently uses the OEM "Boost Relay" as the
contactor between the batteries -- not a bad idea, provided the boost relay
is rated for continuous duty (as I believe all GMC OEM relays are). In
case you're not familiar with combiners, they monitor the voltage on both
of the connected batteries. When either battery is at or above the charge
voltage (usually around 13.8 VDC), a high current relay (in this case the
boost relay) is closed and remains so until both batteries are again below
the fully charged voltage for both of them. In other words, if there's
charge voltage available, the batteries share it, but if they're not being
charged, neither can discharge the other -- they're "isolated".

Your second photo is, obviously, of an aftermarket "tanks monitor panel",
beside an OEM Onan control panel from other than a GMC-fitted coach.

The third photo has the AC circuit breaker panel on the left and the DC
circuit breaker panel on the right -- a much nicer installation than I've
seen in any OEM GMC. Considering the sophistication of the other wiring in
the coach, I'd expect to find an automatic AC transfer switch somewhere to
select either the shore power or the Onan. There may well be an inverter
stashed away somewhere too, possibly with a second transfer switch.

You've got a lot of tracing to do. Unless you find everything labelled, I
encourage you to acquire a Brother label maker and put a "flag" label on
EVERY wire as you identify it. I'm notorious for that habit, and prefer
the Brother label tapes because of their legibility, durability and ease of
production.

Congratulations, you seem to have acquired a nice coach.

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 Sun, Jan 3, 2021 at 3:50 PM Burl Vibert via Gmclist <
gmclist@list.gmcnet.org> wrote:

>
>
> The previous owner also included a nice torque wrench for "making sure the
> wheels are tight"
> --
> Burl Vibert
> Kingston, Ontario
> 1976 GMC, gotta check the VIN
>
>
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NOT STOCK is an understatement!

D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com

________________________________
From: Gmclist on behalf of Burl Vibert via Gmclist
Sent: Sunday, January 3, 2021 14:48
To: gmclist@list.gmcnet.org
Cc: Burl Vibert
Subject: Re: [GMCnet] Another Canadian new owner of a GMC Motorhome

I thought I'd post a few pictures of what I can see of the electrical in this rig. I'm guessing some of this is not stock.