Brake Lights and Turn Signals Not Working After Installing Wiring Harness on 1989 Ford Bronco II

Updated 04/05/2017 | Published 04/04/2017

Products Featured in This Question

Curt Powered Tail Light Converter w/ 4-Way Flat Trailer Connector and Install Kit

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$168.72

Hook Probe Circuit Tester

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$13.69

Question:

Hello eTrailer Team, I installed this kit last night, and dont have brake/signal lights. Instructions state to ground the red wire from the module if the vehicle has a 2-wire system, and attach it to the brake lights for a 3-wire system. My Bronco II has three wires yellow/green for brake and signal, black for ground, and brown for running lights. Should I attach the red wire directly to the trucks yellow/green wire, even though the modules yellow wire is also attached there?

asked by: Matt

Expert Reply:

You have installed trailer wiring harness # C59496 correctly on your 1989 Ford Bronco II. The red wire should be grounded along with the white wire. Make sure the ground location is a clean, bare metal surface.

Brown is for running lights, yellow will be for the combined left turn/brake light wire on the vehicle and green is for right turn/brake lights.

If it still isn't working, then you can test it to see if there is a problem with the converter box using a circuit tester such as # PTW2993. Have someone sit in the vehicle to operate the brakes and turn signals. Test the input wires going into the converter box for the proper signals. If you do not get the proper signals on the wires when the lights are activated, then there is an issue on the vehicle side.

If the input side checks out fine, then test the wires on the output side. If everything works on the output side, then the issue is on the trailer. If you are not getting brake lights and turn signals on the output side, then there is an internal problem with the converter, and it will need to be replaced.

expert reply by: Michael H