This video is about Key components of AC systems on Mercedes Benz W123 W124 W126 W201. Some good info to know about how the system works. For anyone who would like to troubleshoot such systems. A good source of information for anyone who wants to convert from R12 to R134a freon.
Note: The red high/ low speed fan speed switch on the dryer is actually the S32 high pressure AC switch, which is open at 12Bar and closes at 16Bar on US spec W126 (green switch 15/20Bar). The coolant temp switch S25 105C/115C is located on the engine and will eventually switch off the compressor.