The compressor rotates freely and does not make any odd noices during the periods it decides to work. I tried rotating the compressor using the front bolt when the car was shutoff to try to get the refrigerant around to the high pressure side where the combination high and low pressure switch is. This was a big mistake because the air ratchet was able to break the small clutch bolt. So far I am just making steps backwards.
According to a 1998 Mercedes suppliment manual I have, it shows the clutch being controlled by 1) the dash controls, 2) what the book calls an A/C module M19 (it is called a relay on the dealer microfiche and it is called an amplifier assembly on the parts bag) 3) these all go to the AAM along with sensor imputs to control the clutch. The amplifier / relay / module has a 14 pin connection and is located behind the radio. I would like to identify and test the sensors that could be acting up and preventing the clutch from getting a signal. I have replaced the switch on the high pressure line that the dealer said controlled low pressure as well. It has a three pin connection.
The list of fuses and relays that seem related to A/C are k14 comfort functions, F16 back up lights / air conditioning / diagnosis (back up lights are working and fuse looks good) and F44 air conditioning fan (this has the 40 amp upgrade and the fans run when the air works). To test k14 I swapped it with k26 radiator fan (A/C only) because they have the same part number but, it did not change my condition. Any other thoughts?