I am really getting frustrated trying to find all of the 12 volt electrical issues on this coach that has been parked for 19 years. Most will turn
out to be bad connections or bad switch contacts, but I also have some PO rewiring issues. Most wiring is hidden from view which means I am taking
things apart to discover what is behind various covers, lights, cabinets, etc. Also symptoms keep changing which means I have bad connections and
switches in several circuits. I'm having difficulties finding exactly how GMC ran wires.
As an example the GMC wiring diagram show several things on the left side of the coach all wired to the same fuse and the ground sides are all shown
with the ground symbol indicating that each item is grounded locally. I am finding this is not true. As an example I worked on the stove vent and
light tonight When I unplugged the two conductor cable to the vent the overhead light above the couch went dead. It appears that the ground side in
the cable in the vent is wired to the light and not to real body ground. I have no idea were the real body ground connection is located. I have
several of these weird situations with the hall light at the rear and the monitor panel plus this one I am working on. The hall light will be on for
3 or 4 minutes and then go off only to return 5 or 10 minutes later.
In order to chase down these problems I need more than just the wiring schematic supplied by GM and posted on the bdub site. I need to understand how
the cables were run point to point. I also have found some PO modified wiring that does no help when added to the mix. I followed a green wire
tonight only to find it was PO added and ended up not connected to anything and ending under the couch.
I got frustrated and quit for the night. I'll attack it tomorrow but any additional knowledge or documentation on cable routing on a 1978 GM upfitted
coach would be greatly appreciated.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
out to be bad connections or bad switch contacts, but I also have some PO rewiring issues. Most wiring is hidden from view which means I am taking
things apart to discover what is behind various covers, lights, cabinets, etc. Also symptoms keep changing which means I have bad connections and
switches in several circuits. I'm having difficulties finding exactly how GMC ran wires.
As an example the GMC wiring diagram show several things on the left side of the coach all wired to the same fuse and the ground sides are all shown
with the ground symbol indicating that each item is grounded locally. I am finding this is not true. As an example I worked on the stove vent and
light tonight When I unplugged the two conductor cable to the vent the overhead light above the couch went dead. It appears that the ground side in
the cable in the vent is wired to the light and not to real body ground. I have no idea were the real body ground connection is located. I have
several of these weird situations with the hall light at the rear and the monitor panel plus this one I am working on. The hall light will be on for
3 or 4 minutes and then go off only to return 5 or 10 minutes later.
In order to chase down these problems I need more than just the wiring schematic supplied by GM and posted on the bdub site. I need to understand how
the cables were run point to point. I also have found some PO modified wiring that does no help when added to the mix. I followed a green wire
tonight only to find it was PO added and ended up not connected to anything and ending under the couch.
I got frustrated and quit for the night. I'll attack it tomorrow but any additional knowledge or documentation on cable routing on a 1978 GM upfitted
coach would be greatly appreciated.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
