Troubleshooting Trailer Tail Lights Not Working With Tail Light Converter # C56175

Question:

1990 Toyota Celica GT liftback. Installed wiring unit as directed. All tests show good. Trailer light wiring confirmed/tested and operating as normalaux battery used and several tests done checking proper op and ground, jumped using vehicle plug shows good. Plug in connector and no lights what-so-ever. on trailer, tow vehicle operating normally. Tried disabling vehicle ground, same result. Trailer lights are NOT LED. Std. bulbs. Possible converter malfunction? Did not alter harness to temp. by-pass, left as delivered. Again, ALL tests show everything wired properly but when plugged together neg. results.

asked by: Larry C

Expert Reply:

I can only come up with 2 reasons your trailer lights are not working. The first is a wiring issue with the trailer causing an incomplete circuit. I know you mentioned you tested the ground wire but there could also be shorts in the wiring causing the power to not reach the lights.

The other issue may be the wiring on your Celica is not able to carry enough power for the additional lights. While this would test fine and may work on a trailer with LED tail lights, there may not be enough power for incandescent tail lights. If this is the case you may need a Powered Tail Light Converter # C59236. This has a separate power wire which draws power from the vehicle battery to power the tail lights on your trailer. The Converter # C56175 you found puts all the load on the vehicle wiring.

expert reply by: Bud M