I just purchased my 500E and the AC doesn't work. The system had 0 pressure so under the assumption that there is a leak, I vacuumed the system, and put in 4.5 oz of R134a which brought the pressure up to around 70-75psi. I started the car, turned on the AC (temperature knob to 22 degrees, normal mode, and auto fan) but the compressor doesn't engage.
With the pressure switch disconnected and the car started, the engine note will change when the pressure switch connector pins are shorted. However any subsequent opening and shorting of the pins do not have any affect on engine note. Also with the pressure switch disconnected and the car started, plugging in the pressure switch will change the engine note. However any subsequent unplugging and plugging back in the switch has no affect on the engine note.
The compressor does not seem to want to turn by hand when the car is off. Is the compressor seized ?
I appreciate your time !