Troubleshooting Curt Discovery Trailer Brake Controller # C84VV Installed in 2002 Chevrolet Tahoe  

Question:

Expert Reply:

Thank you for your recent purchases from etrailer.

I would like to suggest some additional testing before you return the Curt Discovery Trailer Brake Controller # C84VV. This will help isolate the problem and confirm whether the unit is indeed defective.

The code OL indicates that the controller has sensed an overload condition. Disconnect the trailer from the Tahoe. Apply your grounded tester to the pins at the 5-o-clock and 7-o-clock positions on the Tahoe 7-way, as shown on the linked photo. While your circuit tester (like # PTW2993) is applied to the 7-way pins, have a helper press the manual over-ride on the controller. You should detect a signal after the brief delay. If you do not, then either the unit is defective, or the in-cab installation wiring is bad.

If you do detect a signal when the over-ride is pressed, next have your helper step on the brake pedal. If you again detect a signal, then the unit is working and there is a short on the trailer side that is causing the controller to display the OL (overload) message. Inspect your trailer connector, inside and out, for any signs of corrosion. Inspect the trailer wiring for any signs of cracks or worn insulation, especially around points where the wiring has to bend or where it may contact the trailer frame. A short on the trailer side will cause the OL message.

You can also test the blue wire at the back of the controller. Cut it about 4 - 5 inches from the back of the controller (so you can re-attach it after testing). Apply your tester to the blue wire at the controller and check for a signal when the over-ride is pressed. If you get a signal, you know the controller is not the issue.

Please also refer to the linked article for additional troubleshooting guidance.

expert reply by: Adam R

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