Originally Posted by Francesca Knowles
White as ground is universal in the RV world.
Yes, white is nearly
universally negative. Just as close to universal is a lack of labelling and documentation of wiring; close behind that is the refusal of people working on them to look at whatever documentation exists. All of this leads to assumptions, which are bad. If you don't know what a wire is for, based on reliable documentation of the specific trailer or physically following it to see what it connects to, I suggest not guessing.
I shouldn't be surprised by the reverse battery
hookup since I got partway through doing this myself, but in hindsight it really doesn't make sense. Sure, we may expect black to be negative, but the other wire is white - not red - so shouldn't we realize that what we expect is clearly not
what is happening, so we should do some investigation?