Trailer Brakes Will Not Work and 2006 Chevy Silverado Lights Malfunction w/Curt Brake Controller

Question:

I have 2006 silverado. It had wiring under dash. I bought curt C74VV and ordered harness adapter from you. I cannot get it to work. When first tried it locked up brakes. Now it worked well when tested. Approx 5 min later I have no lights. It doesnt work with trailer and no light without. I have cut connector off I need mating wiring with out connector.

asked by: Robert D

Expert Reply:

It sounds like the red wire in the wiring harness # C51352 was not in the correct place. Take a look at the picture I have included and make sure that the wires in your harness are in the same places. This is the end that plugs into the truck.

It needs to plug in at the junction box under the dash, to the left. It will plug into the spot that is on the top row, second from the left.

The wire functions are white for ground, black for 12 volt power, blue for output to trailer brakes, and red for input from brake switch.

If you decide to hardwire in the controller then the white wire should be grounded to the negative battery terminal and black should go to the positive battery terminal via a 20 or 30 amp circuit breaker (# PK54520 or # PK54530 respectively). But those functions might still work on the connector and will save you a lot of time and effort if you can just use them.

The blue wire will need to run all the way back to the 7-Way and attach in the 7 o'clock position on the back of the 7-Way. You will likely need about 20 feet of wire # 10-1-1 sold in 1-foot increments.

The red wire connects to the cold side of the brake switch. You will need a circuit tester such as # PTW2993 to probe the brake switch wires located above the brake pedal. You need the wire that only has power when the brake pedal is pressed. If it has power with the headlights or turn signals on, then it is not the correct wire. You can use a quick splice connector, # SWC501746-1, to make the connection.