The trailer has two 3500lb axles with 10" drum brakes on each wheel. Yes the wires run through the axle tubes. Here is what I have done as far as diagnosis so far.
1. Had son max out the controller manually to 11 on the meter. I shook, moved touched all the wires and no shorts were shown. The problem only shows up when the trailer is in motion.
2. I pulled all the drums off, checked wires and once again had son put power to the system while I moved the brake arm. No short found. Wires looked ok.
The trailer only has maybe 1500-2000 miles on it - so I thought about the inside the axle tube chafing issue - but my dealer warned me about the warranty issues if I started cutting wires.
I don't think the issue is with the car or the controller, hooked the trailer up to another truck and it did the same thing. It felt different almost like a chug-chug-chug as the brakes were being applied. The biggest issue I have is that the short only shows when the trailer is moving. Only way I can think to narrow it down is to start cutting or disconnecting wires and narrow down where the issue lies.
