12V Power on 7 Way Plug of 2018 Ford F-150 Is Not Powered

Updated 06/19/2020 | Published 06/18/2020

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Hook Probe Circuit Tester

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10 Gauge Wire - Blue Primary - Per Foot

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Question:

my 12v pin in not working on my f150 2018 truck. What do I have to do to get this working

asked by: John P

Expert Reply:

I'll start by saying that it doesn't appear that this would be related to a fuse, since these trucks don't have dedicated towing fuses on them. I would need to know how you're testing this and if you've tested with a trailer connected to it. If you're testing this with the truck running and not getting any power the issue is likely that your truck is computerized, even at the 7-way. It can sense when a trailer is connected based on the voltage draw so it won't sent a signal for 12V when using some testers, especially LED testers because there isn't enough of a power draw.

The system requires a power draw on the 7-way and then holding the brake pedal for about 3 seconds until your dash registers "trailer connected". At that point, the vehicle will deliver the 12V power to your trailer connector and not before. I recommend using a circuit tester like # PTW2993 to test for the 12V power once you get that "trailer connected" message on the dash. That 12V power will be on the 1 o'clock pin location on the 7-way so the corresponding wire will need to be probed to test.

If the issue is occuring with a trailer connected, you'll need to test the wiring as it goes back to the battery source and make sure that it has not been damaged-replace the wiring as needed with a 10 gauge wire like the #10-1-1, which is sold by the foot. If you can't seem to find the issue on the wiring back to the battery, let me know and I can give you a few other steps to try to isolate the issue.

expert reply by: Erik B