Troubleshooting Trailer Running Lights Not Working When Connected To a 2000 Ford F-150

Question:

Installed blinker adaptors due to rapid flash when switched to LEDs.. Resolved the rapid hyperflash for blinkers, break lights illuminate as should when foot hit the breaks BUT the running lights do not illuminate when I turn the light switch to On. What is the issue?

asked by: Brett S

Expert Reply:

First you will want to start with checking the fuses in your 2000 Ford F-150 to verify they are not the issue. If your F-150 uses a factory trailer connector you will need to check the 20 amp fuse in slot 5 of your engine compartment fuse panel. Next you will need to use a Test Light # PTW2993 to test for power to the 4-way or 7-way on your F-150 for the running lights. If using a 4-way the connector is the female connection closest to the male connector. On a 7-way the connector is the one in the 11 o'clock position looking into the 7-way. If you do not have power you can use the test light to follow the wiring back to locate any damaged wires not allowing power to the connector.

With power on your vehicle side connector you will need to follow the wiring from the trailer connector back to the lights to determine where any issues are. Since your turn signal and brake lights are working the issue is on the power side of the light and not the ground side.

expert reply by: Bud M