I am posting here because this is the most popular forum, it is also posted in electrical.

I have the 1997 F-150 with the trailer tow package.
Recently I have a problem with the lights. The right stop light on the trailer stays on all the time (even with the truck ignition off) except when I hit the breaks. Then the right tail light goes off and the left tail light works. Also the blinker on the right side works but slower then the left. This weekend I bought a new trailer and found it was doing the very same thing so the problem is in my truck. Does anyone know where the fuses and relays are for the tow package and perhaps which one is bad?
Thanks...

 

i know that all the trailer lighting controls are in the relay fuse box in the engine compartment on the drivers side. Maybe a fuse is starting to go bad.

 

Sounds like the multifunction switch is going bad. Don't know where it's located. Check your service manual. The brake pedal switch and other things hook into it and it generates the proper electrical currents your truck taillights. The turn signal switch/relay also hook into it. With the electronic flasher relays in these trucks even a burnt out bulb shouldn't cause the signal frequency to change faster/slower.

 

i had a similar problem on my 98 fi50 with trailer tow package, i found the problem was the wires shorting out behind the main trailer plugin,i had to peel the rubber back a bit and low and behold there was some cracked wires shorting each other out.after i fixed it i also put a load of grease in there to prevent this again...hope this helps javascript:smilie('')
smile