Adding a Trailer Brake Controller to a 2004 Chevy Express Van 3500

If your 2004 Chevy Express Van came with a factory installed 7-Way trailer connector then the blue output brake wire will already ran from the back to the front. It is located under the dash near the emergency brake pedal. It will connect to the broke controller blue wire.

The white wire will go through the firewall and attach to the negative battery terminal. The black wire will go through the firewall, attach to a circuit breaker and then go from the circuit breaker to the positive battery terminal. There are 2 kits you can use for wire and a circuit breaker. Use # 5506.

The red wire will go to the cold side of the brake switch. Use a circuit tester like # 3808 to probe the brake switch wires above the brake pedal. You need the one that shows power only with the brake pedal pressed and NOT with the headlights or turn signals on.

If your van has a round plug with a cap inside the drivers side frame rail instead of a bundle of wires in the jack storage compartment, use part # 30955 to add a 7-Way.

If the van does not have any kind of trailer wiring at the back then you will first need to install a 4-Way, # 118377 (if the van has a 4-Way you can skip this step). Next you will need a 4 and 7-Way installation kit # ETBC7. I have included some links that will help with the hardwire of the brake controller and ETBC7 for you.

expert reply by: Michael H