AAG

All of a sudden yesterday, my air conditioning (European 2002 SL 55 AMG) started blowing ambient air. I looked at the unit and the light on the ‘AC Off’ button which should be off is lit. Somehow the AC turned itself off. If I push the AC Off button to turn the AC back on it flashes three times but the red light comes back on indicating that the AC unit won’t switch on. I tested all the fuses and none are blown… I can’t figure out why the AC is refusing to stay on. I have had the SL55 for a month and already had it in once for a battery problem and now this… this is not fun. Has anyone experienced this problem before?


Thanks in advance for any help.

wingless

There is likely a pressure switch on the refrigerant line. Examine the rigid tubing for a fitting with wires. Remove the connector and attach an ohm meter to the switch, not the wires. Fire 'er up, turn the AC on and measure for continuity, It should be close to a short.

If not, there is likely a leak, which permitted the freon to escape.

A.Emgee

My 2000 CLK 320 had the same problem. In addition to the light going on, my auxiliary fan was blowing all the time. It turned out to be a faulty pressure switch.

AAG

So after driving around few a couple weeks without being able to get the AC going and not having the time to take the car in, today, i was stuck in some traffic and remebered something I read in the forum about resetting the AC. I turned the driver side temp control to very cold and the passenger's to very hot and them pressed three keys on the control unit (don't ask me which three because I tried a few combinations) holding the keys pressed for 10 seconds each time, suddenly the AC resetts itself, the light goes and sweet cold air pumps out.

Whatever fault caused the AC unit to stop working needed resetting and (hopefully) it is working now.

mbwhat

sounds like you have a software glitch i have seen it on alot on new 230 and 220 it should be an easy fix for your dealership