Recently, I purchased a 2004 Mercedes Benz S500. The previous owner said he replaced the compressor unit 3 times in the past two years. Shortly after purchasing the car, I noticed that the airmatic compressor would not shut off - even long after I turned the car off and removed the keys. The compressor continues to run after the airmatic is full of air and kicked out.

I located and unplugged the compressor - to shut it off before it burned up the unit. I believe this is the problem that has caused the other compressors to burn out. After I unplug the compressor for a day or so and then plug it back in, the system works fine for a few days - until it sticks and continues to run.

I believe this is the airmatic relay. I'm unsure why the dealership hasn't been able to catch this in previous visits. The dealership has just recommended replacing the compressor.

Any input or similar experiences - with your solution?

Thanks for any suggestions in advance.

Scott