Trailer Brake or Truck Problem?

Artum Snowbird wrote:
Because you are blowing a fuse, that comes from an overload condition. The most likely cause of an overload is a loose connection somewhere. It could be the positive feed, or equally as likely, the negative return. It might be in one particular wheel, or it might be in the main feed.

I would definitely start with both sides of the plug in connector first. The trailer brake fuse feeds out to the brake coils, and comes back on the common return with all the other neutrals. The neutral wire carries the heaviest load always, so a loose neutral is the most common problem, not the positive feed. As the connection becomes loose, it heats up, and then causes corrosion and then you have a higher load than the circuit is supposed to handle, and the fuse blows.

Not to sure where you received your electrical training, however a loose connection will not cause an overload under these conditions. Something is getting shorted to ground to blow the fuse. Common place to look is the brake magnet wires inside the brake assemblies. Chris