I have been chasing an intermittent short in the electric brakes on one of my trailers. Sometimes it’s fine, sometimes it shows a “SH” code on the controller and brakes don’t actuate.
3 days I have been looking for it. I fixed several other little things I found but still had the problem. Started inside the drums. Measured the resistance in the magnets, was fine. Went ahead and packed all 4 bearings while I was in there. Adjusted shoes. Repaired a few places in the wiring I found that I knew wasn’t the problem but for posterity I fixed them.
Found the 7blade connector was a little corroded inside with some rust chunks rattling around in it. Maybe the rust was shorting the brake power, I mean it is on the bottom. Nope
Finally, I decided to just replace the blue brake wire front to back.
It runs down the driver side and then through the axle to the passenger side. Yep, I found it. Mid way through the axle the wire was melted through and just enough to short intermittently.
Who would think a wire riding in a steel tube protected from anything would short…. I guess when the trailer was manufactured, the wire was probably damaged pulling it through the axle and it took 20 years to finally arc through
Rules…
The grandson got the idea (from me

) that real country boys get mud on their bare feet periodically. Wife wasn’t amused.