I have a 1998 F150 supercab 4x4 it came with the tow package with the 7pin round plug. For some reason it works with the headlights but the brake and turn signals do not work. I am getting no juice to the recepticale. I trace the wires back to the plug which is beside the spare tire and I am getting no power to the wires that going to the brake or turn signal. Is there something I am missing????? I don't know what else to check. I would love any advice before I take it to the shop.
Thanks

 

First try pulling the plug apart and test the other side, towards the front the the pickup. If there is power there then the back half of harness has broken wires. If not then try testing the wires (turn signal and brake) up farther along the frame rail. if there is power up there then the wire is probably broken somewhere between your test spot and the plug. If there is power up farther it more then likely broken behind the fuel tank. I would run a jumper wire from there back to get power for now until you could remove the gas tank to fix the wires. If you don't have power all the way up pull out the light switch check if maybe a wire was somehow melted and maybe arcing. Also if you have an ohm meter test the switch itself you might find the problem could be there as well. When testing the switch there is a certain procedure in doing so, you have to test each pin in a certain order with the switch in a certain position. Maybe your local repair shop could help you find this information or if you have a repair manual for your pickup it should tell you in there. There is also a certain ohm reading for each pin in each position if one is higher or lower then what is stated I would replace the switch and see if that helps.

 

Not exactly sure when ford went to the additional fuses for trailer tow, check the owners manual for the location of the fuse. As I understand your problem, running lights work but turn and stop don't. Go back to the power source. Dumping our trailers into the water can blow fuses. But all good boaters disconnect the harness before we launch. Right? RIGHT!

 

That was the first thing I checked all fuses okay. I am taking to the shop thurs we will see what the verdict is I am done with it. Sometimes you have to know when to fold them.

 

Boat Man,

I have this same problem with my '98 F150. What was the verdict?