Community Forums

howardlw · 07-31-2018, 11:09 AM

I need a 12V wiring diagram for my, new to me, 1989 Executive Diplomat 40 ft Detroit Diesel Diesel Motorhome. Any help is appreciated..HW

BFlinn181 · 07-31-2018, 12:11 PM

Perhaps if you can explain why or what issue you're having more help can be given without an actual wiring diagram for a 29 yr. old RV.

howardlw · 08-20-2018, 11:39 AM

It is rude of me not to have responded earlier with a thanks at the very least.
The repetitive problem I am having is that at night the headlights will suddenly shut off, leaving only the marker lights on.
The interior lights still work, as do the dashboard lights, fans etc
If I wait a few minutes the headlights snap back on. and we are on our merry way, for another 10 or 15 minutes, then click from under the dash and they shut down again.
Some other events may cause the effect. Shifting gears or engaging the Jake brake.

Any ideas...Howard

ps..still looking for a wiring diagram. hw

BFlinn181 · 08-20-2018, 12:36 PM

It would help if you tell us on what chassis your RV is built. The headlights would be an issue with the chassis wiring. Sounds like either someone put higher amp headlights than the circuit was designed for or an auto reset circuit breaker is tripping, cooling down, and resetting. I'd start looking for the source of that click, I believe that is the auto reset breaker.

HarveyP · 08-20-2018, 02:47 PM

I had the same problem. The headlight switch would overheat and shut off until it cooled down. I solved the problem by installing 2 relays, one each for high and low beams. Now the headlight switch only carries enough current to trigger the relays. I found the instruction in this forum. Good luck, HarveyP

BFlinn181 · 08-20-2018, 03:04 PM

Quote:

Originally Posted by HarveyP

I had the same problem. The headlight switch would overheat and shut off until it cooled down. I solved the problem by installing 2 relays, one each for high and low beams. Now the headlight switch only carries enough current to trigger the relays. I found the instruction in this forum. Good luck, HarveyP

I'd think a headlight switch heating up and shutting off could easily be proved or eliminated by putting your hand on the back of the switch when the lights go off. I'd suspect an auto reset breaker more than a faulty switch.

howardlw · 08-21-2018, 10:25 AM

Thanks to all...The coach is a,
1989 Executive Diplomat 40 ft Detroit Diesel Motorhome.

Skip426 · 08-21-2018, 10:38 AM

Quote:

Originally Posted by BFlinn181

I'd think a headlight switch heating up and shutting off could easily be proved or eliminated by putting your hand on the back of the switch when the lights go off. I'd suspect an auto reset breaker more than a faulty switch.

Many of the headlight switch used in vintage motor homes ; including my own 99 , use a mid 70's GM P/U headlight switch , that has a built in self resetting circuit breaker. My 64 Plymouth , 68 Coronet , and 73 Dodge , all had similar C/Bs built into the headlight switch. I had problems with all three when I changed to high powered headlights and adding relays was the cure.

Considered a safety feature at the time , in the case of an overload on the headlight circuit , the lights would flash back on momentarily to allow some vision for the driver to stop safely .
BTW : You didn't have to go under the dash , the headlight switch knob and shaft would burn your finger tips.

BFlinn181 · 08-21-2018, 10:39 AM

Quote:

Originally Posted by howardlw

Thanks to all...The coach is a,
1989 Executive Diplomat 40 ft Detroit Diesel Motorhome.

According to NADA, an '89 Executive Diplomat 40' is on a Gillig chassis. Gillig is still in business, you might contact them for wiring diagrams for the chassis.

https://www.gillig.com/

Skip426 · 08-21-2018, 10:45 AM

Quote:

Originally Posted by howardlw

Thanks to all...The coach is a,
1989 Executive Diplomat 40 ft Detroit Diesel Motorhome.

Have a look up under the dash , if the headlight switch looks like the picture below , It's from a 72/78 GM , P/U and has a built in C/B, if it takes mins to re-set , the C/B is worn out , should re-set in 5/10 seconds and on a dark highway that's long enough to give you grey hair.