Your use of the word "slapdash" tells me that you're educated and gentlemanly. I would have used more disparaging words! LOL. Yes, as Aaron said, most of those external devices are wired by local dealer. Your attention to such details would indicate an engineering or technically skilled background. You are not likely to find that in the RV service industry.
As one other poster said, fix it yourself, and move on. Trust me, a test light or voltmeter, together with a few crimp connects, some electrical tape and your wiring knowledge will make you many friends in the campgrounds. What people don't know about this stuff would fill a book!