Troubleshooting Hopkins Reliance Brake Controller on 2008 GMC Sierra 1500

Published 11/11/2019

Products Featured in This Question

Replacement Brake Control Plug-In Harness for Tekonsha and Draw-Tite Brake Controller 12" Long

(727)

$15.51

Digital Multimeter with 42" Long Test Leads - LED Display

(3)

$21.73

Cordless Circuit Tester

(15)

$19.27

Tekonsha BRAKE-EVN Trailer Brake Controller - 1 to 4 Axles - Proportional

(169)

$80.69

Question:

I have a Reliance trailer brake controller and a 2008 GMC Sierra 1500 SLE truck. My problem is the controller is receiving power with the brake pedal extended or brakes off. This is happening with the trailer hooked up and causes the trailer brakes to stick. With trailer not hooked up the controller will read E-1 or 2.0 while brake pedal is extended or brakes off. . If I pull the brake pedal out with my foot power goes away? Any suggestions?

asked by: Chad C

Expert Reply:

The first suggestion I have is to replace the Hopkins Reliance brake controller, which despite its name is an unreliable brake controller, to say the least. You can still get an economical brake controller that is far more reliable with the Brake EVN # TK63VR with Brake Control Harness # 20127 for your 2008 GMC Sierra 1500.

In regards to the issue you are having, an E1 code on the Reliance means a trailer is not connected and there are a number of potential issues you will need to troubleshoot steps which I'll go over with you. You will need to find out if the issue is on the brake controller, truck, or trailer. To test the brake controller, sever the blue wire a couple inches from the back of your controller. Then use circuit tester # PTW2979 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.

If the controller tests fine, reconnect the blue wire and move on to the truck side trailer connector. Often, corrosion or dirt may be the cause of a short in a trailer connector. Check the plug to see if there is any type of corrosion built up that may be hampering its functionality.

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.

If the truck side checks out then it could be the wiring to the brake magnets or possibly the magnets themselves. Inspect the power wires to the magnets and look for wires that may be pinched or otherwise damaged and fix as necessary. You'll also need to make sure the ground wires are attached to bare metal surfaces and free of any paint, dirt or corrosion.

You'll want to visually inspect the magnets; if you can see the copper windings coming through the magnets will need to be replaced. To test the magnets use Multimeter # PT89ZR and follow the help article I have linked to guide you. I have also attached some help articles on testing and troubleshooting brake controllers for you to check out which I strongly recommend reading.