Should Vehicle Tail Light Still Work If Power To The C67WR Converter Module Is Cut Off?

Updated 01/07/2026 | Published 01/06/2026

Question:

Hello- Trying to help a friend diagnose a problem with his Curt 56464 wiring harness. If the 12V battery power is cut off from the harness power converter, the vehicle lighting brakes, turn signals, etc. should still operate as normal, correct? In other words, if the 12V is cut off, only the trailer lights should go out. Thank you in advance for your answer. Dan C.

asked by: Dan C

Expert Reply:

Hello Dan, thanks for reaching out. Yes, you are right. If power is cut to the converter module, the vehicle lights should still function like normal. That signal is still being sent from the car to the rear lights. Without power to the converter there would be no trailer lights, but the vehicle lights should still work.

Are you having a problem with the Curt # C67WR harness? What is going on exactly? When we see problems with these its usually a bad ground, the module is not wired directly to the battery, or the plugs are not seated all the way. If you want to explain what is going on I am happy to look into it and see what can be done to help.

expert reply by: Jesse M