Troubleshooting No Trailer Lights Working with 2011 Ford F-350

Published 07/12/2019

Question:

no trailer lights at all .every thing fine on truck lights?

asked by: J. W

Expert Reply:

If you aren't getting any trailer lights at all I first recommend testing the connector itself on your F-350 with a circuit tester like # PTW2993. Test the pins while you have a buddy run through the lighting functions in the cab. If you don't get power at the connector, then you at least know the problem is on the truck.

If this is the case, I first recommend inspecting the connector for any debris or corrosion around the pins that needs to be cleaned out. Check the wiring immediately behind the connector to make sure the connections are secure and there aren't any exposed or pinched sections of wire.

The next thing you will want to check on the truck is the fuses/relays under the hood and inside the passenger compartment fuse box. I looked through the online version of the owner's manual for your 2011 F-350 and found that there are 15 amp fuses located in the number 13, 14, 15, and 30 positions inside the passenger compartment fuse box in charge of trailer lights. Under the hood fuse box there is a 30 amp fuse at the # 26 position, a 10 amp fuse located at the # 70 position, and a 25-amp fuse at the # 100 position. There are relays at the number 29, 74, and 75 position.

You will want to check these fuses and relays to make sure they are all present and in good condition.

If when testing the truck's connector, you DID receive power with a circuit tester like # PTW2993, then the problem is somewhere on the trailer. Make sure the trailer side connector is free of any debris/corrosion and make sure all of the grounds are securely connected to clean, bare metal surfaces.

If you are still having this problem please let me know and we can continue to troubleshoot.