Trailer Stop/Turn Fuse Locations in 1997 Ford F-150

Question:

I have a 1997 Ford F150 in excellent condition with factory wiring harness. When i connect my trailer, I dont have left and right turn signals or brake lights on the trailer. Running lights are ok. I checked the owners manual and replaced the fuses associated with turning lights, still no blinkers or brake lights. We connected the trailer to another truck and all the lights worked properly, so we ruled out the trailer having issues. Is there another fuse or relay that is not labeled as trailer lights or turn signal lights or brake light that could cause this issue.

asked by: Peter

Expert Reply:

There may still be fuses/relays that are missing or damaged. On my Ford the owner's manual fuse block diagram does not match the actual fuse box (!) so I recommend you check both the manual and the lid of the fuse box which should have a legend telling you what function each fuse supports. Since you have the issue on both sides of the truck this tends to suggest the problem is not a damaged wire.

The online manual I reviewed shows the stop/turn circuits are protected with a 15-amp fuse in position 1 in the power box at the lower left side of the dash. There is also a secondary power box in the engine compartment that has a fuse for trailer stop/turn lamps, a 20-amp fuse in position 2. I linked a diagram showing this location.

If you have a circuit tester like # PTW2992 you can test the two stop/turn circuits on your connector. On a 4-pole these are the contacts for the green and yerllow wires.

expert reply by: Adam R