I got the inductive ammeter out and measured the current at each brake. I couldn't find the problem.
I connected the meter to the appropriate wire, then pulled the emergency breakaway cable to set the brakes. I then quickly read the current and reset the emergency breakaway. Here are the readings (in amps):
I don't see anything there to indicate a fault.
While I was talking to the guy at BrakeSmart, he told me that many brake short fault messages are triggered by poor wiring at the cable. I recently installed a Pulliam Pull-Rite hitch, and that required an extension of the trailer connector. I wired up an extension cord to complete the installation.
Since I didn't see any problem at each brake, I dismantled the plug that I wired and inspected it. I didn't see anything wrong, but went ahead and re-connected all the wires. A couple of connector screws were not as tight as I would have liked, but otherwise everything seemed okay.
I am now unable to duplicate the problem, so maybe there was some single strand of wire in the plug that crossed to an adjoining screw. That would probably be enough to cause the fault indication. I sure hope that's the case, since I am not going to do any more with this until I pull the trailer again.
I inspected the wiring that leads from the brakes into the trailer bottom. It is well protected, being two single wires, each individually insulated, that are formed into a cable by another outer covering. It looks like a small Romex cable.
If the brake short fault shows up again the next time I tow the trailer, I'll probably replace all the magnets or backing plates. I called our local Dexter axle supplier and the magnets sell for $24. An entire backing plate is only $66, and you get new shoes with that. These brakes are not worn much, so I really don't want to rebuild them yet, but I will if I have to in order to solve this problem.
Thanks again for all the great suggestions.
2012 New Horizons Travel Trailer (formerly an Airstream owner)
2008 Dodge 2500 diesel with Equal-i-zer hitch.