Did you check the fuse out in the Power Distribution Box under the hood.. It's fuse position 4 and a 20 amp fuse for the trailer lamps..

 

Yes I did (before I came to Ford Forum) - it was blown. I replaced it and now have 12v in & 12v out of this mini fuse. I have 0v at the factory connector coming off the frame at the rear of the truck where the wiring to the trailer connector plugs in. This is with the truck park lights on. I have a good ground at this connector location.

 

i Had to bring my truck in for service (because one of my Head had a CRAK) I had them check on my Trailer lights. They said Like HayaPower it is the Relay wich is part of the entire Box (nonservicable) they wanted to replace the whole Box 7hundredandchange....... I told them i would pull a new wire (and thats what I did) and put a Relay and a Fuse Holder (total cost 10 Bucks and twenty minutes of work).

If you have the same trouble let me know and i would be more then happy to help you out........


And again THANKS to HayaPower for all our help.

 

Thanks for the update, and glad you were able to add in the circuit..

99 has a replaceable relay in the I/P relay box centered to the instrument panel...

 

Hayapower - Thanks for the info on where my relay can be found. I'll let you know when I locate it and get it replaced. I assume the IP relay box can be seen without taking the IP apart? You said it is in the center of the IP, I'll look there. Sounds like Merkur had to go to extremes to get his trailer lights working. Glad he got it done. Thanks again for the information. Paul

 

I know this is an old thread, but was wondering if 2002 Ford F250s also have the trailer running light relay integrated into the fuse box (Central Junction Box). I hope it's different for the 2002!!!

I've read just about every post on all of the Ford truck forums, and this is a common problem. However, I have not seen a good solution or a good method to troubleshoot the problem. I've done the basics like checking the ground, verified the other pins on the tow connector are working, and they are. Also checked the applicable fuses in the fuse panel with a meter, and they are good.

My only plan right now is to start tracing the wire from the hitch connector to the fuse box.

If anyone has any ideas, and/or a circuit diagram that you could send my way, I would really appreciate it.

Thanks,

Bob
Beaver, PA
Cell 724 561-78727
reboles@gmail.com