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Diagnosing Faulty Trailer Wiring Harness on a 1993 Ford Ranger


I have a 1993 ford ranger STX. I purchased a trailer light converter from Etrailer a year or so. I am having a problem with the camper tail lights. The only thing that works consistently is the running lights. Brake and turn signal lights are intermittent. I think it is the converter. I checked my ground connection on my truck, it has only 1omh of resistance to the terminal connector. example Left turn signal light may work, but right turn signal one wont. If I disconnect the 7 pin connector and reconnect, then the right one will work, but then the left one wont. If I apply the brakes, I might get one tail light to work, and sometimes none. If I was to disconnect and use a test light, I find that it is working correctly.


Expert Reply:

The issue you described sounds like a bad ground but could also be attributed to a faulty converter box or corrosion. I would first check the grounds. The best way to do this would be to remove each of them on both the trailer connectors and the lighting assemblies. I recommend sanding down the surface with some sandpaper and then attaching with new hardware.

If the issue still persists once the grounds have been checked then it would also be worthwhile to look inside the trailer connectors for corrosion but if none is present then the issue is likely the converter box. You can replace this using the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # 118325.

expert reply by:
Conner L

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