Voyager Brake Controller has 12 Volts All the Time on Blue Wire and Does Not Sense Trailer Connected

Question:

I have 12v on my blue brake wire at the truck plug all the time. The light on the controller doesnt come on when I hook up a trailer. controller is not new it has been on the truck for many many years and has worked in the past. What could cause the blue wire to always have 12v and why does the green light not ever come on?

asked by: Ty

Expert Reply:

Having a constant 12 volts on the blue wire can indicate an internal problem with the controller or a short to the brake output wire. To test it you will sever the blue wire a few inches back from the controller. Then use a circuit tester such as # PTW2992 if needed to test the end coming out of the controller. It should only show power when the manual override lever is applied. If it shows power at any other time then there is a problem inside the controller and it will need to be replaced.

If the blue wire shows power at the correct time then reconnect the blue wire and then go to the rear of the vehicle to test the trailer connector. Again there should only be power when the manual override is applied. If there is constant power all the time then there is a short you will need to track down and fix.

A likely culprit is a dirty or corroded trailer connector. Clean the connector inside and out. Corrosion can cause a short and can build up on the pins and also at the back of the connector where the wires attach. If the problem persists then trace the wires from the 7-Way forward and look for any broken wires with exposed copper strands touching metal and fix as needed.

If the problem only happens when a trailer is connected then it could be an issue with the trailer wiring or magnets. Make sure that the trailer side connector is clean and free of corrosion inside and out. Examine the magnet power wires and make sure there are no breaks in them. And make sure that the main trailer connector ground and magnet grounds are attached to clean and corrosion free bare metal surfaces.

Visually inspect the magnets and if you can see the windings coming through they will need to be replaced. To further test the magnets you can follow the FAQ article I have linked to the right. I have also included a link to our FAQ article on troubleshooting brake controllers for you.

If you determine the issue is the brake controller, I recommend the P2, # 90885, as a replacement. It is our most popular controller because it is easy to set up, easy to use, and its reliable.