While installing and checking operation, as I activated the brake controller manually, the slide knob popped off and I cannot get it to snap back into place. Im also not getting a green light, but I havent gotten started troubleshooting the truck or the trailer. Its an older trailer and the magnets may need to be replaced.
asked by: John W
I made you a short video that shows how to replace the knob provided that the little tabs on the back of the knob or where they mount are not damaged.
When you do not get a green light, that means that the trailer is not connected, there is a short to the brake output wire, or there is a bad ground connection. It could also mean that there is no power going to the controller black wire. Use a circuit tester like # 3808 if needed to determine if power is on the black wire.
Then, sever the blue wire behind the controller a few inches, use the circuit tester to test the end on the brake controller side for power when you apply the manual override. It show power when the override is on, and no power when off. Any deviation from this indicates a problem inside the brake controller and it will need to be replaced.
If the blue wire does check out, make sure the white ground wire is attached like it is supposed to be. If you used a plug-in wiring harness that just plugs into the vehicle, it is unlikely the ground is the issue. If you hardwired it, make sure the ground wire is attached directly to the vehicle battery.
Move on to checking the trailer and vehicle side connectors for dirt and corrosion and clean them out. Corrosion can also build up behind the connectors where the wires attach. Make sure the main grounds are attached to clean and corrosion free bare metal surfaces.
The next step is to check the brake magnet wiring. Make sure the grounds are attached to clean metal surfaces. Look for bare wires that may be touching the trailer frame. Then visually inspect the magnets. If you can see the windings coming through the magnets will need to be replaced. I have included a link to an FAQ article on how to further test the magnets.
expert reply by: Michael H
Products Referenced in This Question
Tools for Wiring
Product Page this Question was Asked From
Time Delayed Controller
2 - 4 Brakes