My F350 has an electric gremlin. When I turn on the light switch, key on or off, the lights come on. But when I turn the switch off, the lights do not go off. I have to pull the fuse and then they go off. When I put it back they stay off. I tried pulling the relays under the hood but it did not affect the lights. Is there a relay that could be stuck somewhere? I tried another switch but it did not do anything. Thanks for any help.

 

There is a relay that controls them. I believe that it is under the dash (drivers side) I'm pretty sure that it is a timer relay. You said that you changed a switch, have you sprayed the latches with wd-40? Is your door ajar light on?

 

The door ajar light is not on. It is all the lights that stay on, headlights and running lights. There is a 20 amp mini fuse that I pull, under the hood, to shut everything off. Whatever the problem, I did not know about it before because the fuse was burned out. It was only since I replaced the fuse that this started to happen. I have only had the truck a short time and never had a trailer hooked to it before. It started when I was hooking up a trailer and checked the lights. I had signals and stop lights but no running lights. I looked at the mini fuse and saw it was bad. When I replaced it, still no running lights on the trailer, and the lights do not turn off. This is with the trailer plugged in or not and key on or off.

 

Maybe Jim's on to something with the timer relay. Have you left the lights on, closed the door and then just watched to see if they stay on permanently or go out after a while?

 

If I have this right it is your exterior lights that are acting up and not your interior (dome) lights. If it is the interior lights I would look at the headlight switch. I had a 98 F250 7.3 the headlights went out found a blown fuse, the headlight switch practially melted and blew the fuse.

 

Yes, the exterior lights are the problem. If I turn everything on and then turn the switch off, all the lights stay on. And I still have no running lights to the trailer if I hook it up. And I tried a new switch but it did not help.

 

have you checked the trailer plug at the stock harness behind the back bumper ??? check and clean all plugs under there....are your lights on a timer?? try waiting a couple minutes and see if they go out....

 

I don't think they have a timer. They always went out when I turned the switch off before. I guess the trailer running lights are a seperate issue. I will check the plugs for that part. Is there a seperate relay for the truck lights somewhere? I tried all the ones under the hood,

 

http://www.7point3.com/AETips/Docs/Fuses.pdf

scrole down for diesel trucks..

 

Here is the wiring diagram for the 01 F350 with out daytime running lights. The only thing that I can see (I'm going to print it out and study it more) would be the switch on the steering cloumn.

Sorry I could'nt up load the pic.
Here is where i got it:
EBSCO Publishing Service Selection Page

 

It took a while but I found the relay. It is behind the dash just left of the radio and down a bit. There are 3 relays together. A big blue one and 2 smaller black ones. It was the black one towards the front of the truck. If you pull the radio you can get to them. I would think Ford could have put them in a better place.

Thanks for the help. I appreciate it.