GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.

Home » Public Forums » GMCnet » Another Canadian new owner of a GMC Motorhome (introduction)
Re: [GMCnet] Another Canadian new owner of a GMC Motorhome [message #361398 is a reply to message #361394] Sun, 03 January 2021 15:24 Go to previous messageGo to previous message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma:
Senior Member
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
>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org



Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: Trailer Lighting for Coach Without Factory Trailer Lighting Option
Next Topic: Question for a "friend"
Goto Forum:
  


Current Time: Mon Jul 08 01:03:19 CDT 2024

Total time taken to generate the page: 0.01083 seconds