I'm runnning a 2001 f-150 supercrew. I recently noticed that my RIGHT blinker/brake light stopped working in both of my hook-ups (4-post and 7 way round). I'm not sure where to begin, and I recently bought a 16 foot trailer that I need to pull on Monday. Any help would be great. All other running lights/blinkers/markers work. Thanks!

 

There are different fuses for trailer lights. one each 10 amp for left and right brake/taillight. They are located in Power Distribution Box under hood. On drivers side.. Look in owners manual or check all the 10 amp fuses... If fuse blows again there may be a short in trailer wiring.

 

Or you just have a burnt bulb. Do the "parking" lights still work?

 

On a single bulb there are 2 filaments, one for turn/brake and another for park light. The park light runs on a different wire and fuse than the turn/brake. Turn/brake is divided into right and left side in wiring as well as fuse.

Fuses under the hood....like raisin said...most likely culprit....still might have a short in the trailer though causing fuse to pop.

 

Since the brake light is missing from both the truck and trailer, it's not very likely (but still possible) that burned out bulbs are the problem.

There are no fuses that can affect only one rear lamp. Sorry.

The single brake lamp signal from the pedal switch goes to the multi-function switch MFS. The MFS splits the brake signal into front and rear and left and right signals. From there, it's a straight shot to the rear of the truck for the towing adapter and the actual brake lights.

I'd suggest inspecting, cleaning, and testing the MFS switch. Its connector pins and the harness have cause problems on a lot of different Fords. If the connector is in good shape, the MFS is probably defective. The service manual gives specific point-to-point checks to test it before replacement.

Steve

 

Which is why I was asking if it's just the brake/blinker or if it was the brake/blinker light and the running light.

If it's just the brake/blinker not working, then it's probably just a burnt bulb.

 

I don't see where he said the truck's light wasn't working. He just said it didn't work when he used either the 4 pin or 7 pin hookup, nothing about the actual truck.

 

The way he said it makes me think truck light works, trailer hook up doesn't. The '99 "Ford" wiring dia shows a different 10 amp fuse for rt/left light (towing circuit only). Just a good way to keep a trailer light problem from hurting truck. These are in the same box as the tow relays. I think it was a darn good idea and hope they haven't done away with them in 2001. These fuses and relay are only in trucks with the "Trailer Towing Option" or if someone installed them later. If someone taps into the tail light circuit thats a different deal, but I don't think that what we have here. Page 95-2 2000 Ford F150 wiring dia Fuse 19 right stop/turn lamp......Fuse 20 left stop/turn lamp 7 pin/4 pin towing only located in the Battery Junction Box.

 

Check your turn signal switch. put the blinker on and try tilting the steering wheel to different positions and have someone watch your lights. I had it happen to my 2001 supercrew whenever you changed the tilt on the wheel. They changed the turn signal switch twice, and it turned out to be the connection at the switch in the column. i guess it stretches and pulls loose. Check with the service mgr at the dealer, there might be a t.s.b. on it by now.