Hey, my roof AC unit all of a sudden started to kind of buzz and vibrate even with the unit turned off, no fan on. I can feel it vibrating if I touch the ceiling inside. Any ideas what this might be??> It was working just fine on auto, starting and stopping based on thermostat setting. It also ran on fan only, hi or low. I ran the fan from midnight last night until around 8 am this morning and then turned it off. about two hours later it started to vibrate like i said before without turning it on. If I turn off the circuit breaker and then turn it back on, it was quiet and did nothing. I have left it off because I am afraid it might start humming/vibrating/etc., when I am not in trailer. Strange????