E1 Error Code on a Hopkins Reliance Trailer Brake Controller

Updated 10/20/2022 | Published 06/24/2012

Question:

i have a dodge 2004 diesel, with a reliance electric brake, and the code is e-1 what do i need to do to fix this.

asked by: Mike H

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.

It is also possible that you have blown 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

Randy K.

7/8/2020

I am trouble shooting a problem with the Reliance brake controller on my RAV 4. The E1 error code comes on when I brake, instead of the braking level. This happens with the trailer connected or not. I have checked the connector and tested the trailer brakes unconnected and they work. How can I find the cause?

Chris R.

7/13/2020

I'm thinking there might be a loose ground on one of the brake assemblies. Check each of the brake assemblies on the trailer and make sure the ground wires are all still securely attached to CLEAN bare metal on the frame. If this doesn't clear the error let me know and we'll go from there.

M L.

9/30/2021

@ChrisR still not working. On 4 different trailers

Les D.

10/21/2021

@MLanger: Let's get a voltage multimeter like the Performance Tools # PT89ZR. Disconnect the trailer and measure the voltage where the blue wire comes out of the dash mounted brake controller. There should be no voltage until you press the red override button on the controller. While pressed you should see a voltage of 12 to 13 volts. If you don't have voltage there check the check the black wire coming to the controller that supplies the 12 volts. If you don't have power there, you will need to trace that wire back to the power source checking any inline fuses that you find. If you have voltage on the blue wire then go to the brake wire pin on your rear bumper connector. (On a 7-way pin this should be the one in the 5 o'clock position. I have attached a document with excellent illustrations of all trailer connectors and their pin-outs. If you don't have voltage there then you have a break or crimp in the blue wire and it will have to be fixed or replaced. If you have voltage there, the reconnect the trailer and check the voltage at each brake. Repair or replace wires as needed.

Helpful Links

faq-wiring.aspx

Shannon

10/10/2022

@LesD I checked the blue wire as you said. I have power all the way to the 7-pin on the bumper. However, I noticed that when I disengage the break there is still a small about of power on that pin (the light on my tester gets really dim). When I engage the brake, the light on my tester gets brighter. Is this normal? Also to back fill my story, I installed the controller per the instructions and got the E1 code. When I hooked up my trailer the E1 code remained. I pressed the manual control and the trailers brakes locked up. I unplugged the controller and was able to move the trailer. In troubleshooting I disconnected the harness and wired it back up again making sure the wires are correct. This time the E1 code does not show up when the trailer is not connected. Instead it shows nothing, but when I press the grey increase/decrease buttons, it shows me the amount, all while the trailer is unplugged. When I plug the trailer in, nothing changes on the controller, I can adjust the settings. When I press the break I hear a high pitched hum at the trailer brakes, is this normal? I have not tried to move it yet to test the brakes as I want to make sure all the wiring is correct.