Troubleshooting Curt T-Connector Vehicle Wiring Harness for 2019 Jeep Cherokee

Updated 04/07/2026 | Published 03/30/2026

Products Featured in This Question

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

(197)

$102.54

Question:

I hooked up my wire harness . I have running lights but I dont have brake lights or turn signals

asked by: Xavier E

Expert Reply:

Hey Xavier, I'm sure we can figure out the issue.

Since your running lights are working, we know the harness has power and ground. That usually means the issue is either a loose connection at one of the taillight plugs, a fuse, or possibly the converter box not picking up the brake/turn signal.

What I’d do try first is to reseat both T-connectors by unplugging and plugging them back in to make sure they're fully clicked in.

Next is checking the ground connection to make sure it's attached to bare metal.

Verify the vehicle's trailer/tow lighting fuses and left/right turn signal fuses.

Last would be testing the signal into the converter using a multimeter. Turn on the running lights and check the brown wire.
Turn on the left/right turn signal and check the yellow and green wire. Press the brake pedal and check both yellow and green wires. There should be a 12v reading to confirm power.

If you’re seeing all of that, then the Jeep and connections are doing what they should.

If everything looks good going into the box, but not coming out then the converter is likely bad and the harness needs to be replaced.

What are you connecting this harness to; boat trailer, utility trailer?