samhain7 wrote:
So how can I check if the problem is really fixed? Multi meter?
I sure wouldn't just assume the problem has been "fixed" ... get a polarity tester like that recommended by
rockhillmanor and check your source supply to make sure it's correctly wired, no wires loose, etc. Assuming it is then plug in your trailer and use the same tester in the trailer to confirm there aren't any errors being introduced by the trailer. Assuming no errors are found it's probably safe to say you've found the source of your problem but from here on in do what
rockhillmanor and I and many others do
every time we camp - test that source supply with a polarity checker
before you plug in.