I have a 2001 F250 and my running lights on the trailer aren't working.

I have a flat 4 pin connector on my truck and I used a 4 pin connector harness with leds to test functions. Turn signals work, brakes work... Just no running lights.

I have checked all the fuses under the hood and they are good. I tried to find another fuse in my manual for trailer lights but didn't see anything.

Is there a fuse under the dash that runs the running lights for the trailer somehwere? If so, anyone have an idea on the fuse number?

****EDIT****
Just got done checking all the fuses under the dash as well. All good.
****EDIT****


Thanks!

 

You need to check the "brown" wire if the trailer wiring is proper color coded

you did turn your headlights/park light on to test running lights?

 

Correct, I did turn on headlights.

My buddy was saying there might be a relay somewhere behind the radio? The harness used for the trailer brake controller he said was really close to it and sometimes the relay goes bad...? I will get my multimeter out and check the brown wire on both the 4 plug connector and the 7 plug connector.

Thanks for the info.

 

No voltage on the brown wire to either plug.

 

Here is the owners manual for your truck Look in the fuse section there seems to be a couple of fuses or relays that could be at fault.
2001 Ford F-250 Owner's Manual - JustGiveMeTheDamnManual.com
It looks like on page 175 -176 It could be fuse 4 located in the power distribution box located under the hood. I had a similar problem on a 2002 f250 I had but the fuses were located differently from 2001 to 2002 There are fuses just for the trailer wiring

 

Thanks. I looked at fuses 4 and 8 multiple times, they are good. My brake controller lights up just fine. I pulled every fuse in both compartments and ohmed them out. No bad fuses.

It's got to be a relay, but the manual doesn't state where it is.

 

For some reason I am wanting to say it is one of the larger square fuse that is under the hood in the power distribution box. I want to say it is fuse 100. Of course my memory isn't what it what was, but it's worth checking out.

 

Trailer Tow Backup Lamp Relay #38

Doesn't show location. I imagine its one of them relays under the hood separate from the main box. going to try swapping #38 for another relay.

 

No dice. I may just end up running a seperate wire for the running lights for the time being. Tie them into my license plate circuit for now.

 

The trailer tow relay is behind the left-center of the IP, in the same relay block as the turn signal flasher. To locate it, remove the radio, turn on the flashers, and follow the clicking. The relay of interest is right next to the flasher.

The output of the relay is a brown/white wire that runs to the rear of the truck. Corrosion in the several connectors from the cabin on back is pretty common.

 

I had the same problem and what mine turned out to be was the harness at the back of the truck. Unplug the tow harness to see if you have 12 volts at that plug. Work your way forward until you get 12 volts.

 

Always check fuses then move to the rear of the truck and take the plug apart. Loose, dirty or corroded wires and connections and bad grounds are usually the issue.

 

The trailer companies love to use crimp connectors to connect everything, even the plug pigtail to trailer. On a 12v system it does not take much corrosion to screw the connection. I just ran into light issues with my one trailer. Turned out the jack brushed the plug pigtail and pulled the wires out of a couple of the crimp on connections they used to connect the plug to the trailers wiring. I got rid of those garbage connectors and soldered/shrink tubed it now. I'll probably rewire the whole trailer when it gets warmer.

 

Had the same problem. Finally ripped into my new tailors and found a wire that must of been in the way for the mouse to fit into a little hole so he removed about an inch of it

 

When ever I havetrailer light problems that I cant figure out easily.......the first thing I do is always make sure The trailer lights have a good ground! A poor ground canscrew with your mind real bad