Which fuse or relay controls the stop and lights for a trailer in tow? My turn signals work on the trailer but the lights do not. The lights work on the F-150 but the trailer lights do not.

If the problem is a relay, how does one check for whether it is good or not?

Thanks.

 

The proper fuse/relay for the item you are looking for can be found in the owners manual.. If you don't have the original one, you can download it here.

https://www.fleet.ford.com/maintenan...ls/default.asp

Just enter in your specifics and go from there.

Have you tested the trailer connector at the bumper yet? You'll need a test light (it looks like an ice pick, but has a light bulb in the handle and a ground wire and you touch the end of the pick to the connector.. If you get a light, then it's a good connection...)

Could just be a bad connection between the trailer and the truck?? I've had that happen to me before, and all I had to do was crimp up the plugs connectors so there was a better connection between the plugs.

If you don't get anything on the truck side, then you have to start tracing back from there to the next connection point and try again. Keep moving back until you get a connection. This assumes the fuse/relay is working..

If you are getting power to the rear of the truck, then check the connection on the trailer and then you have to start tracing from the hitch back to the lights on the trailer...

Check your ground, as that's usually the problem in most cases...

Good luck!

Mitch

 

There is no electricity at the connection. I have electricity at the left and right signals but there is nothing from the brown wire (trailer lights). I traced it back to the loom. That is why I think it must be some fuse for trailer lights. I called our Ford service person and they didn't have a clue.

I'll keep looking and if I can't find it, I'll run another wire from the pickup lights to the trailer connection. By the way, I completely rewired the trailer to no avail.

Larry

 

Humm.. Well Larry, it sounds like you have it mostly covered... I don't know if you use a fuse or a relay for the trailer lights, but it should have it's own space for it in the fuse box.... Your turn lights will have it's own separate space as well, so it still could be the fuse that's causing your problem for the running lights??

The manual will have a diagram for your specific year of the fuse box layout and what space you need to look for depending on the function you are looking for... (you never confirmed that you have verifed the fuse is ok or not??)

Mitch

 

The fuse for the right turn signal was burned out and I replaced that right away. The left signal was OK. The problem is that there are several fuses which could be for the lights. One is a pink 30 amp box-like fuse. It is all right.

I put the trailer on another pickup and all the lights lit up like they should, so the problem is with the F-150 but tracing it is pretty tough.

It would be nice if some mechanic read this forum and could come up with the answers. Like I said, I called the local Ford dealer technician and of course, the electrician wasn't there today.

Thanks for your help. I'll probably have to make an appointment and pay Ford a hundred dollars to find out which fuse is blown. They charge $85 an hour, here.

Larry

 

Check fuse#10
Trailer park lamps