Troubleshooting Trailer Lights Not Working on 2011 Ford F-150

Question:

My owners manual agrees the common fuse for both landr should be in slot 73 in the power distribution box but there is not a fuse in that slot. I put one in but no change. Also It may not be related but the first sign of trouble was my aftermarket brake controller is flashing ER. When I connected the trailed is when I found none the trailer lights are working. And yesterday without the trailer connected all the gauges died but reset when I restarted the truck. That may not be related either. Seems odd coincidence. I cant find a blown fuse and it looks like power is present in the power distribution box. Since its all the lights could it have lost ground? I know its Halloween is my truck possessed? : Thanks KF

asked by: Sam F

Expert Reply:

Since you have power at the fuse box and no blown fuses I would start by checking the 7-way at the rear of your truck for power using a circuit tester like # PTW2993. This will help you narrow down if it is on the vehicle side or trailer side. You can also check the connector for any debris or corrosion.

Assuming it is on the vehicle side the ground connection would be a good place to start. You can also work your way along the wiring to check for a short and repair as needed if you're able to access the wiring.

As for the brake controller, it sounds like you have a Tekonsha like the # 90195 with that ER error which is an internal error. You can unplug it and plug it back in to see if that clears once you sort out your wiring issue. If it doesn't then the only solution is to replace the brake controller.

expert reply by: Robin H