I have a 97 Expy with 142K miles on it. I purchased a new travel trailer and just recently picked it up from the dealer. All the trialer lights worked on it.

I went to move the trailer the other day and the running lights on the trailer do not work. Turn signals work, brake lights work. The running lights do not.

I pulled fuses and all of the check good with an voltmeter. I did some more research and I found out that in the engine compartment there are some relays. I moved all of the relays to different sockets to see if one was failing and I still have the same issue.

The connector on the truck looks great All of the wiring that I can tell looks good also.

I even went so far as to jumper the hot and running lights on the camper (an campground trick I am told) to light up the trailer to check the circuit there. They all work also.

I am out of options and want to camping but cannot without the safety of the lights

HELP!!!
RoG

 

Can you voltmeter the female connector on your truck to see if the running lights are getting power?

 

Follow the trailer plug outlet pigtail wires about 2 feet. You should find 2 connectors that the pigtail wires plug into. It was corrosion at these connectors that caused my trailer lights to not work.

 

I have checked the femail end of the connector and there is no power getting to those pins. I have followed the wiring harness up to the pigtail and the connectors and wires all look great. I see that the wiring harness goes up behind the evaporator for the AC and then towords the front of the truck.

Any other ideas? Fuses good. Wiring good. Connecotors good. I swapped the relays around in the engine compartment and they all behaved the same. HELP!!!!!

 

First off, I really should do a spell check before I post!
I was able to find the relay the powers up the running lights. It clicks every time that I turn the head lights on. If I pull that relay the headlights still work so I am guessing that this is the correct relay.

I swapped this realy with another of of the same part number (there are several next to each other in that box) and I still do not have any running lights.

I would gather then since the fuse is good and the realy is working that I have a wiring problem.

Does anyone have a wiring diagram or ping outs from the back of the vehilce to the fuse/relay panel?

 

Did you specifically check fuse F1 (20A) in the large under-hood fuse box? That is the one that protects the trailer running lamp circuit.

Here's a link over at the sister site regarding this same fault on a 150. The circuits are identical.

http://www.f150online.com/forums/ele...t-working.html

Steve

 

I did not check that one yet. I just did and a I have wonderful Lights! Thanks for all of the help!!!!