E1 Error Code on Reliance Brake Controller

Question:

I have a 2003 GMC Yukon XL my reliance brake controller will in the middle of the night and randomly during the day read E1 and turn on my brake lights while vehicle is parked and locked up. All I have is the controller with the factory plug plugged into its slot under the dash. Also is it common if you push the red test button for it to run on the rear lights as well.

asked by: Rocky M

Expert Reply:

The E1 code on your Hopkins Reliance brake controller is an indication that there is no trailer connected. The most likely cause of this is that one of your connectors is corroded and needs to be cleaned. The fact that the lights of your Yukon XL are coming on also indicates that you may have a short in your brake controller.

To test the brake controller, sever the blue wire a couple inches from the back of your controller. Then use a circuit tester such as # PTW2992 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override; if it shows power at idle then there is an issue with the controller, and it will need to be replaced.

You will also want to test the brake output pin on the 7-way socket; it should only show power with the manual override. If it shows power any other time, then there is a short somewhere between the connector and the brake controller you will need to find.

I also strongly recommend getting a high-quality brake controller to replace the Reliance. The Prodigy P3 # 90195 is the most popular model we carry due to its effectiveness and ease of use. The P3 activates your trailer's brakes immediately in proportion to your Yukon's brakes; it offers three different boost levels so you can adjust your braking power and has five storable settings for things such as braking power, boost levels, and display settings. The P3 will automatically level, has constant diagnostic checks, contains safeguards which defend your controller against shorts, and features an LCD display which is much easier to read than that of other controllers.

For your 2003 Yukon XL with the factory 7-way the P3 will work by simply plugging it in with wiring adapter # 3015-P. I've added a link to a video review of this controller for you to take a look at.