Troubleshooting a Brake Controller that Activates When Parking Lights are On
Question:
I have a 2001 GMC with a reliance brake controller #47284 when my park lights are on with out trailer hooked up I get E-1 error code and if trailer is hooked up and lights are on it applys brake to trailer
asked by: Cooper S
Helpful Expert Reply:
The E1 Error code on the Hopkins Impulse Brake Controller # HM47294, indicates that there is no trailer connection. There is something funny going on with your brake controller wiring. It sounds like the running light circuit is shorting out to the brake output circuit or stoplight circuit.
What you can do is use a circuit tester like part # 3808 to test all 4 wires of the controller with the parking lights off and on. If the brake output circuit sees 12 volts when the lights are on then you know you have a short. You should also test the stoplight circuit in the same way as it could be shorting to this circuit as well.
Once you track down which circuit has the short on it you will need to track down where the short is at. It will most likely be where the controller wires into the tow vehicle wiring or at the trailer connector at the rear of the vehicle. Here you would need to look for corrosion or exposed wire and fix as needed.
The running light trailer wiring circuit could easily be shorted out to the brake output circuit at the 7-way connection of the vehicle.
