Troubleshooting No Trailer Brakes with Autowbrake Brake Controller

Updated 10/01/2019 | Published 09/30/2019

Question:

Hi, I just installed the Autobrake brake controller on my trailer because I didnt want a controller in the truck and I wanted to use different tow vehicles. Everything works when I clip it to a test battery. But when plugged into my truck, only the lights work. I have a feeling that the truck is not delivering power to the electric brakes. pins 1 and 2 of the 7 pin plug. The blue and white wires is there something with the truck that would cause this?

asked by: Barry E

Expert Reply:

The white wire from the Autowbrake Electric Brake Controller # 3430001 is for ground so you will just want to make sure it's securely attached to a clean bare metal surface. A weak ground can definitely prevent proper operation on the brake controller but you shouldn't ever get power on this circuit.

When you mentioned that only the lights work when you plugged it into your truck, are you referring to the LEDs on the Autowbrake itself or just the rear signal lights on the truck and trailer?

If the lights are working on the Autowbrake then you know the black 12V circuit is connected and powered appropriately. This does leave the blue brake output wire that you mentioned as the possible culprit. Make sure this is securely attached to the brake output wire on the trailer that goes to the individual brake assemblies. You may need to trace this wire as far as you can to make sure there aren't any pinched or damaged areas that need to be replaced between the 7-Way and the brake assemblies. Also make sure each brake assembly is securely grounded to the frame.

If you have another tow vehicle handy you might also connect it to the trailer to at least rule out your Silverado as being the problem.

If you still aren't getting power to the trailer brakes please let me know and we can continue to troubleshoot.

expert reply by: Chris R