We went to fire up our RV (it got crashed by a tree branch) after 4 weeks in the shop and the condenser runs, but not the blower. It hums but I am scared to leave it run and burn something up. We have it plugged into an adapter and are using an extension cord for power; could that be the problem? Not enough juice? We have hooked it up this way before and had no problems, but with a heavier weight cord (also broken in the crash). :D