schamran

Unplugged the tail lights, trailer wiring, and removed all splices in the stock wiring, and a fuse lasts 3/4 away around the block, so it's an intermittent problem. Headlight switch?

Chrisreyn

Probably..

schamran

Put a new headlight switch in... Fixed nothing. Again, the tail lights and trailer wiring is all unplugged, and I'm still having trouble. Any obvious places I should start? I need to drive it to an interview tomorrow that's 3.5 hours away, and I suspect I'll be driving home in the dark.

Chrisreyn

Obviously you've checked the fuses?
OK, then start at the fuse block and trace the wiring for your running lights.
The wiring diagrams for the 91.5 located in the Stickey are pretty correct for almost all 1st gens..
If you are blowing fuses, it would likely be a short to ground.. look for fraying or burnt areas on the wiring harness, also check the plug connector for the headlight switch, they can get hot, melt and cause a short.

This article may help you in tracing the wiring..
http://dens-site.net/Dodge_CTD/1991.5-Wiring_Diagrams/
and this one is about the running light circuit:
https://www.dieseltruckresource.com/...g+lights+relay
sorry I lost the pictures for that thread, but with teh wiring diagram, it shouldnt be hard to trace the circuit

schamran

Yes I have checked the fuses. Thanks for the info!

Santaclaus

Check the wiring where it runs along the frame and behind the fuel tank. Also check the wiring in the front going to the front parking lights and side marker lights. There are several places that the wires could get pinched. Another method to check would be to take the fuse out and substitute a backup light bulb then go under the truck and start pulling pushing and generally raising heck with the wires until a lightbulb lights up. This is with all the lightbulbs removed one of the oldest ways I know to find an intermittent short. Just my two cents, Mike.

schamran

That's genious!

j_martin

For us old timers, it's common practice.

Chrisreyn

schamran, any update on this? Im curious as to how ya solve it..

schamran

I was missing a bulb in one of the fender marker light, and the harness was hanging in the fender well. I didn't have a bulb so I taped it up, put a new fuse in, been working well ever since.