Trailer lights not working ???

[dalejiw25]

Hey all. My TV is a 2000 F-150 w/ 5.4 Triton. I have good trailer brakes but my clearance, stop and turn signal lights aren't functioning and there doesn't appear to be any blown fuses. Weird, Any suggestions ??

[handye9]

dalejiw25 wrote:
Hey all. My TV is a 2000 F-150 w/ 5.4 Triton. I have good trailer brakes but my clearance, stop and turn signal lights aren't functioning and there doesn't appear to be any blown fuses. Weird, Any suggestions ??

All your trailering fuses and relays, are in the power distribution box (under the hood).

Here is a link to an owners manual. See pages 182 - 185.

[Dragonfly]

I tow with a "heavy duty" payload and tow package Ford F150. My problem is the reverse. Tail lights, brake and turn signals work but the dash info regularly tells me "trailer disconnected." Apparently Ford has a reputation for issues with its trailer brakes and trailer connection. Google it. I was told that the trailer was recognizing the truck, thus the working lights, but the truck was not recognizing the trailer, thus the message and MAYBE no brakes. After cleaning the hell out of the contacts and strapping the plug in with a locking pull tie, I have not had the problem for the last month or so. The Ford connection is very temperamental but, it does work, I hope. PS: I also chased bad grounds but didn't find any in the truck or trailer.

[thomasmnile]

You mention the fuse doesn't 'appear' to be blown. Did you check continuity with a multimeter? Reason I ask is these 'new' style fuses can look fine and be bad. On a recent trip our trailer's marker lights quit working though everything was fine when we hooked up. Pulled into a rest area and proceeded to check fuses that protect the trailer harness circuits (3 or 4 of 'em on our Ram 3500 I discovered). Sure enough, a 20 amp fuse labeled as trailer marker lights was bad. New fuse, problem solved.

[RoyB]

I believe there are two or maybe even three fuse panels... My 2010 has one on top of the radiator and another on inside the truck on passenger kick panel side. I think I have a third one on the drivers side up high behind the dash...

My 2004 ford had one under the hood and one on the passenger side kick panel or maybe behind the glove box. That may have been where my JEEP inside fuse panel was haha...

Check for additional fuse panels.

Some of these circuits maybe controlled by the small plug-in relay on the fuse panel. Alot of circuits like to use a relay that is under control of the ignition key to turn off alot of things at the same time...

On my 2010 Ford I think the lines that feed the 7-way trailer connector all have separate fuses also mounted inside the truck somewhere.

A good tool to carry in your RV tool box would be one of these trailer connector testers... You can plug this into the trailer connector and it will show proper small lights for all of the functions. Great troubleshooting tool. I got mine from AMAZON but have seen them at auto parts stores.


I always squirt a little WD40 in my trailer connector before hooking up and wiggle it around abit to make sure all the blades are making good contact.

Roy Ken

[Passin_Thru]

You can try a 12 V trouble light also. Start at the plug. Check to see if you have contact inside the plug ends, then pull the plug on the trailer apart and see if a wire is disconnected.

[TucsonJim]

I would suspect a loose or corroded ground connection. Try using a meter to trouble shoot per the attached diagram.