Travel trailer brakes not working

[442xx]

2011 Salem, 2014 Durango TV:

Just wanted to let everyone know in a general sense to not overlook “corrosion” as an issue:

Originally hooked up the Salem and all the brake lights worked. Halfway (100 miles) to our campground, the brake controller read “d.c.” which means “trailer disconnected”.
Closer the campground I got dash messages of “left turn signal out” and “right turn signal out”.
Side note: Once at the campground our AC to DC converter failed (intermittently putting out 10v to 14v DC). I replaced that. THANKS SHADY MAPLE RV for having one in stock and not gouging me.
After numerous resistance checks and voltages checks. I decided to clean the TV ground connector. Using a nail file worked great. I then got good ground resistance on the TV. Hooked up the Durango to the Salem, brakes and lights all work now.

I added the side note just in case the converter intermittently going kaput may have caused high current and therefore the high resistance (corrosion) on the ground lead.