I purchased a used Class A -- All works well, but am having problems with using 12V. Human error? or mechanical/electrical?? We did not have electric hookups, so was able to use the generator (worke...
Bad ground. Clean and re-tighten all battery connections and find where the negative attaches to the chassis, unbolt that and wire brush the hell out of it.
Also, some coaches switch the negative side on what's called the salesman switch. Check the connections on that and squirt some contact cleaner in the switch.