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brwerder · 10-02-2013, 06:37 PM

I have a 1991 Affinity with a Cat 3208. Tonight it would start but had no dash lights unless you pull the light switch and it also had no power to the shift control or heater controls. I went to the rear start and tried it and it had them after starting that way and when I sat back in the seat and touched the heater control it all went back off (I don't thing touching it had anything to do with it). Went back and shut the engine off and started it again. This time it all stayed on but when driving the gauges would jump around sometimes on their own. I know a lot about vehicle electrical systems (I was GM flat rate technician for 15 years) but I need some wiring scematics to help diagnose it. The manuals have some, but nothing that shows circuits that go to the dash or the triggering relays for it all. Does anyone have the complete scematics for one of these?

Thanks Brett

deandec · 10-03-2013, 08:52 AM

Brett, I have some .jpg files of the wiring schematics for my later rig. But no general schematics.

I have had success using the wire numbering list "from" and "to" to create my own understanding of what the scheme is.

I have no schematic for the chassis relays, but the wire numbers connected to the relays and the wiring number list may yield a clue.

I do have schematics of things like the ignition system, supplement to ignition system for EPM, chassis wiring, battery boost. But I suspect you have similar schematics. They likely do not do what you need.

It does sound like a loose ground wire somewhere that is causing your gauge and lights flickering issue. But I suspect you already made that conclusion.

If you see value in any of the above, I can send copies.

brwerder · 10-04-2013, 07:38 PM

Thanks Dean for the comments. The night I posted up the questions I was a little frustrated with the schematics, but you work with what you have. I did dig into the wiring number system and came to the conclusion that my problem had something to do with an 80 amp continuous current relay/solenoid inside the driver side electrical box area. It powers the heater controls, Allision shift control, dash gauges, and the cruise control. Since it was intermittent I figured to go to the ground for the trigger first and found a ground bus inside the dash and it had a loose main connection and many of the wires on the bus were corroded. I removed all the wires and cleaned the bus and all the wires and re-assembled with silicone grease. I thought I will give it a try and see if maybe that was all it was. Left for a 500 mile ride this morning to Myrtle Beach and about 100 mile in I had the first hint I still had a problem. The cruise kicked off a few times, so when I got to Winchester I stopped at Camper World to see if maybe they had a relay. They did not, but told me where the local Napa Truck parts store was. I went there and they had the relay/solenoid and it was only $24.00 with tax. I figured at least if it completely failed I could just stop at the next rest stop and put it in. So, it did completely fail about 300 miles down the road and I knew you could still drive it but what I did not know was that the warning buzzers with go off constantly. Had to tolerate that for about 10 mile and stopped at a truck stop and put the new relay/solenoid and we are working 100% now. All is good again in old motorhome land. Again - thanks for the thoughts.

Brett