Troubleshooting Non-Working Light Signals After Installing A Curt Tail Light Converter Wire Harness

Updated 06/28/2024 | Published 06/20/2024

Products Featured in This Question

Curt 2-to-3 Tail Light Converter for Towed Vehicles w/ Incandescent Tail Lights

(79)

$25.94

Hook Probe Circuit Tester

(62)

$13.94

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(15)

$92.25

Question:

I installed the Curt tailight converter in my restored 1981 casita trailer. Left signal works until I brake, then both signals alternate off and on. Also the right signal doesn’t work, then both alternates off and on when brake applied. Do I have a faulty converter? Or is this some sort of grounding problem?

asked by: LARR C

Expert Reply:

Hey Larry,

A faulty ground can cause all sorts of goofy problems so it's a great place to start your troubleshooting. I'd check the ground for the tail light converter # C56196 as well as the ground for the lights. Are the lights on the trailer LED? If so you'll need to install resistors # TK32VR for each circuit for this converter to be compatible. From there you can doublecheck that you have the wires connected to the appropriate tail light wiring on the towing vehicle to ensure the correct signal is coming in to the converter box. If all the wiring is good and then you can probe # PTW2993 into the wiring before the converter box and see if the signal is coming in correctly and then check the wiring after the converter to see if the converter box is defective.

expert reply by: Kevin C

Larry C.

6/27/2024

Kevin thank you. My tow vehicle is a 2024 Ford Maverick. I just got a RECALL notice regarding their “taillights”. They are going to reset some sort of computer glitch regarding the taillights. Hopefully this solves the problem!!! I think it is the problem. I may know after today when my appointment is over. I can follow-up to confirm for you.

Kevin C.

6/28/2024

@LarryC If the tail lights have an issue to begin with then that could very well be the cause. Keep me posted and we can keep troubleshooting if the recall work doesn't fix it.

Larry C.

6/28/2024

@KevinC The Maverick recall did not fix my taillight issue, but this is what happens; Taillights & brakes work until I apply brakes when signal is applied. When brakes are applied and I turn on a signal light, the signal blinks on and off. When it blinks off, Both taillights blink on! My ground wire ahead of the converter is tied to the running lights on the side of the trailer and to the taillights mounting frame which is aluminum. I’m going to check the grounds again but can’t get to it for a few days. I’ll keep you posted. Thank you.