E1 Error Code on a Hopkins Reliance Trailer Brake Controller for a 1989 Chevy 2500

Question:

When i press the breaks i get an error code e1 even with the trailer hooked up. the breaks do not work. i checked the power to the blue wire. I get 10.5dcv before i push the red button. when i push the red button then it s down to .597 dcv. i have checked all of the wiring and replaces just about everything. i have a good solid clean ground. any ideas would help.

asked by: Mike M

Expert Reply:

The E1 error code on the Reliance brake controller indicates that a trailer is not connected. If the trailer IS connected and you get the E1 code, a probable cause is a dirty trailer connector. Check the trailer connector on the trailer and on the vehicle. Clean out any dirt or corrosion. Corrosion can build up behind the connectors where the wires attach as well.

However, the fact that it shows power without braking and then shows less with the override applied indicates that the controller is most likely bad. Disconnect the red wire and test the voltage output on the blue wire and if it shows power without the override and/or still does the same then the controller is bad.

You can also check the stop light fuse. Check the owners manual for the location of the stop light fuse and replace it if needed. A blown stop light fuse would cause the brakes not to work with the brake pedal. If the 3rd brake light on the truck is not functioning, it is a sure sign that the fuse is blown. Use a tester on the red brake controller wire to make sure it shows a signal when the brake is applied.

You can also examine the trailer brake magnets themselves. If you see the windings coming through then they need to be replaced. I have included a link to an FAQ article for you on how you can further test the magnets.

expert reply by: Michael H