My 1995 W140 S320 has recently developed a weird probelm that whenever I start the car again after it has rested for a short time, the A/C compressor doesn't engage. In that event, I would shut down and restart the engine and the compressor engages again and works in perfect order until the next engine shut-down. Except for that, the A/C is freezing and I don't see any other things being abnormal. That does not happen at the first start of the day but just occurs when the car has been used. After reading the valued article "Mercedes-Benz A/C Control Diagnostics, Steve Brotherton, ImportCar, June 2000" on this site, I decide to start with the basic - The compressor control relay and the low/high pressure switch. Would anyone please tell me the exact locations of them on the W140 and their part numbers if possible? If there is any other idea about the problem, please suugest. I greatly appreciate any inputs.