On a recent trip I had my convertor running (growling) and really nothing on in 12V. I was puzzled because this was OK when I had a lot of lights on, but would stop when I tirned them off, but this tr...
I would definitely get then checked out. Just imagine driving for a several hundred miles with one foot on the truck brakes...
Each brake magnet will pull around 3AMPs...
Be on the safe side and somehow confirm you still have good trailer brakes... Both the magnets and the brake shoes can all be used up by now after being ON for a couple of days...