Troubleshooting Magnetic Tow Lights That Do Not Display Brakes But Do Display Turn Signals

Question:

I have magnetic tow lights on my car. I have the 4 wires going into a 7 way female socket. Everything is functioning well, except the brake lights. Is there a way I can fix this??

asked by: Paula

Expert Reply:

A set of 4-pole-equipped magnetic tow lights such as the Optronics # TLL21RK will carry both turn signal and brake lights on the same wires. The green wire carries right turn and brake signals and the yellow wire carries left turn and brake signals. The brown wire carries running lights.

Since one of the functions on these two wires is working and the other is not the problem would appear to lay upstream of the lights, on the motorhome side. I also do not know if you are using some type of adapter to connect the 4-pole to the 7-way socket. We offer items like the Pollak # PK12716 that plug in at the 7-way and provide a receptacle for the 4-pole harness on your lights. If using an adapter like this make sure the contacts are clean (free of visible discoloration, dirt and moisture) and that the adapter is fully seated in the 7-way. It is also possible that your adapter is wired differently than the MH.

You can also test your motorhome's 7-way socket for correct functions using a tester like # PTW2993. Please refer to the linked video showing how to use the tester and to the linked article which shows you the usual pin configuration on motorhome wiring. I also included a photo of a 7-way.

expert reply by: Adam R