Truck Does Not Show Trailer Connected After New Junction Box Installed

Question:

The truck does not show the trailer is connected. I installed a new junction box with new 8’ cable and connector pre installed. Wired the trailer per the diagram and how the old one was wired. And the brakes just don’t nt register as connected. Truck works with other trailers no problem. The ground is only wired to the trailer frame on this trailer. Could that be the problem? This trailer also has a battery on board that seems to be wired to the aux. Any help would be great. I included a picture of the previous wire set up on the old box. New one is the same. The connection of the battery is a little odd to me. I have included the picture of the battery connections as well.

asked by: Justin

Expert Reply:

It does indeed sound like there is an issue with the trailer's brake output circuit. The photo's unfortunately do not reveal much info but what we can do is apply a direct 12 volt power lead directly to the brake output pin on the 7-way. Once this is done we then need to take a circuit tester and start probing this wire while working our way back. This should then allow us to identity where the power stops. If you end up getting power all the way back to the braking assemblies then we know the issue is with the magnets. If you can let me know what your axle capacity is I can get you a set of replacements.

Also, don't forget to check the ground wire for the braking assemblies themselves.

expert reply by: Conner L