trailer brake problem

dryfly wrote:
Recently installed 4 new electric brake assemblies and Prodigy P3 controller. Worked great for 800 miles.

Plugged the trailer in one morning and got a "Short" error on the controller. Checked all truck/trailer wiring and nothing evident. Next time I plugged in trailer I got an "Overload" error. Prodigy tech support this does not indicate a short to ground but that the system is drawing too much current.

This has evolved into a highly intermittent issue with the brakes working about half the time and getting the "Overload" the other half. I have eliminated the truck and controller as being part of the problem.

Obviously it has to be wiring in trailer or brake magnets causing the problem. The error will not occur with the truck setting still, but it just doesn't react like a wiring issue, and should show up as a "short" error if it was wiring.

Is it possible that the magnets could be breaking down internally under load of breaking??

The magnets should be fine with the miles indicated. Unless the assemblies were installed wrong...

Both controller messages are indicative of trailer side wiring issues. First place to start is the cross over wire inside the axle housing. These chafe and the insulation cracks causing both types of error.

Short error would be a cross connection on the brake positive and negative wires.

Overload could be multiple issues, but most common is brake positive contacting the axle housing.

Check any wire nuts and scotch lok wire connectors -they fail but look outwardly fine.