I just bought a 24 foot North Country with a Coleman air conditioner in the ceiling. When connected to 110 power a small fan or compressor intermittently comes on even when the air conditioner is totally off. The fan (if it is one) is not the main fan which is much louder. This one is noisy enough to be bothersome at night. If I unplug the trailer, it stops, but that is not the solution. How do I shut the noise off? Also, what is it?