Troubleshooting No Left Turn/Stop Brake Signal on OEM Connector for 2006 Ford F-150

Question:

2006 Ford F-150 factory trailer harness 4 way left side of trailer inop. No 12v coming from 4way plug. Top pin-ground,next pin-lights,next pin left side trailerno voltage bottom pin-right side trailer. Checked all fuses,relays now what am I missing?

asked by: Stephen M

Expert Reply:

Since you've already checked the fuses and the pins for the 4-Way on your 2006 Ford F-150, the next step is to use a circuit tester like part # PTW2992 to test the wiring for the left stop/turn trailer light function. To determine if it's your connector or the wiring go ahead and disconnect the US Car connection at the back of the OEM plug and check the pin for the left stop/turn (see attached example).

If you are getting power to that pin then you need to replace the connector with something like the Hopkins # HM40975, but if you aren't getting power to the US Car connection then you need to start using the pin to test that specific wire. Follow it and look for any places where it is pinched or damaged and fix as necessary.

That should fix your problem but if it doesn't then you may want to use the wiring kit # HM40975-11998 and splice in to the circuits that are working but then tie the left turn/stop in to that circuit behind your tail light.

expert reply by: Jon G