I fear my air suspension compressor has failed

Last night I parked my car to go into a store. Upon my return I heard what sounded like a fan running in the front drivers side of the car which I have never heard in the nearly 7 years I have owned this car. When I tried to start the car, it made a loud noise presumably from this same unit that was running when the car sat idle. I smelled a strange sweet odor thru out the car. The engine seemed to fun normally. I again shut the car off, and this loud noise continued when the car was off until it finally stopped after about a minute. When I turned the car on again, the ride sensor lights both came on and the could not be raised or lowered. It is stuck in a mid range position. Based on my description, I am assuming that the suspension compressor is fried, and Im not dealing with a fuse or module failure. Would you tend to agree? It was the coldedst night of the year at 12 degrees.