Trailer Brakes Engage When Headlights of1997 Ford F-250 Turned On

Question:

Hello, I have a 1997 Ford F-250 and found out the hard way that when I turn on my headlights, the trailer brakes activate. I purchased a tester and plugged it into my truck and everything shows that it works properly. Also when I had another vehicle plugged into the trailer, the brake lights are dim and the turn signals dont work properly... Any sugestions will be greatly appreciated. The trailer is a 2006 Attitude 21k if that helps.

asked by: Jonathan

Helpful Expert Reply:

Since you've already tested the trailer connector on your truck and the trailer also has issues when connected to another tow vehicle it sounds like the problem is likely with the trailer's wiring.

Check the trailer's wiring for any damaged points. You'll also want to make sure the trailer connector is clean, both on the pins and the back where the wiring is connected to it. The issue could be that the connector is wired incorrectly. I've attached a diagram showing the standard wiring. The brake circuit should be connected to the pin in the 7 O'clock position when looking into the connector. Another thing to verify is that the ground connections are well grounded on clean, bare metal surfaces.

If you still can't find the problem after checking the trailer wiring, let me know and we'll do some further troubleshooting.

expert reply by: Charles S