Wiring a 1997 Chevrolet 1500 Without Towing Package for 7-Way Trailer Connector and Brake Controller

Question:

My truck did not come with the tow package so Im upgrading to tow a camper I recently purchased. The owners manual says that there is a 7 way harness tied back under the rear between the rails. All I found there was the 4 way leads. Am I not looking good enough or is the book just generic and my model doesnt have a 7 way? I bought the whole kit to wire direct but if a harness already exists it would make life easier. Also any suggestions on going through the fire wall and where is the stop light cold side of the brake?

asked by: Joseph C

Expert Reply:

The wires you are looking for under the rear end are a blue and an orange wire. They can be located above the spare tire or on the frame rail. The blue wire carries the brake output voltage, and the orange wire would be used for the 12V accessory power from the battery.

If present, these wires end in the engine compartment under the master cylinder, down near where the brake lines turn to pass under the cab. They are wrapped up with electrical tape, and can be difficult to find. If the wires cannot be found, you can always run the wires to the rear using what was supplied in the # ETBC7 kit.

When running the wiring through the firewall, you can use an existing opening if you can find one, if not you will have to drill your own. Make sure any opening that you are wanting to use to pass wiring through has a grommet. Not doing so can result in the wires being cut by the metal and shorting out on the cab.

The stoplight switch in those model years can be difficult to access. If you cannot reach it and test the wires exiting it with a circuit tester, you can tap into the circuit further down the line. The wires can be accessed in the wiring harness under the steering column, the wire is either light blue or white. Use a circuit tester, item # PTW2993, to probe the wires until you find the one that only shows voltage when the brake pedal is pressed. Tap the red wire on your controller into this circuit.

expert reply by: Mike L