Troubleshooting No Power to Trailer Connector on 2012 Ford F-250

Updated 07/17/2020 | Published 10/23/2017

Question:

I have a 2012 Ford F250 that all of the trailer lights turn, brake, running have stopped working. There is no power on the 4 or 7 pin plugs. I tested all with a meter. They worked the day before. I have checked 3 fuses in the passenger compartment fuse panel in the truck #13,14,and 15. I have checked 6 fuses in the power distribution box under the hood #22,26,29,74,75, and 100. I have switched the relay from the blower motor to test the relays. These are the only things I can find that would have anything to do with the trailer lights. I am out of options. Any suggestions?

asked by: Joey W

Expert Reply:

If all the fuses and relays appear to be in good shape on your 2012 Ford F-250, then it's possible that there is an issue with the wiring behind the trailer connector. I recommend first simply inspecting the connector itself for any corrosion and making sure the wires are securely attached. Then trace the wiring forward on the truck as far as you can, looking for any damaged areas, exposed wiring or loose connections, simply fixing as needed. If your F-250 has the factory 7-Way, you can also take a look at the round connector on the truck where the 7-Way harness plugs into.

Lastly, when taking a look at the online owner's manual for your F-250, I did see that the 15 amp fuse located in the number 30 position in the passenger compartment is also used for trailer lamps. You can check that fuse to make sure it is in good condition.

If you are unable to resolve the issue, please let me know and I will be happy to look into this further. I have also attached a wiring troubleshooting article that you might find helpful.

expert reply by: Chris R

7/7/2020

I have a2012 f250 I have no power to my running light pin and no power to the electric brake pin on the 7 pin connector on my bumper pulled coin slot to see if there is power going to tbc and there is , does this mean I have a bad tbc ?

Chris R.

7/13/2020

This honestly doesn't sound like there's an issue with the brake controller. The controller also wouldn't affect the trailer running lights circuit. Check under the hood of your F-250 to see if there's a blown fuse that needs to be replaced - the truck's owner's manual will tell you exactly where the trailer running lights fuse is located. As for the brake controller circuit - can you tell me how you're actually testing this?

7/13/2020

@ChrisR I was testing with a voltage meter, I checked all fuses prior to testing harness. One I figured out all fuses were in good order I started doing voltage test on harness to blue wire “ electric brake wire” one I established there were 12 volts when brake pedal is depressed. I tested pin for electric brakes on the female 7 pin on bumper. Long story short after doing Continuity test and receiving a good feed bad and running and Oms test found that there was high resistance on the electric brake wire. Cut wire out of harness and7 pin and over laid a wire from harness back to 7 pin . Issues solved.