Original Autel Diagnostic Tools

Car model and year: 2007 Mercedes ML350 Symptom: AC just stopped working, but the fan went on high. What I tried to do: Went to have it checked and was told that there was an obstruction on the system and Compressor no good. So I replaced the Compressor, Dryer, Expansion Valve, AC Pressure Sensor, Ambient Sensor, and replaced all seals. Did a 2-hour vacuum, let sit for 1 hour to see if had any leaks. But when I’m trying to charge the system, after the 2nd 12 oz can, it doesn’t want to accept any more refrigerant as it seems that the Compressor is not activating. Checked the voltage and there are only 4.2 volts. I replaced the Climate Control Switch w/another used one to check, but still all the same. What should do next? When there is a problem in the A/C system, the A/C Control Module will prevent the compressor to operate. The code/s must be read to see what the problem is. After replacing the component, according to the code #, the code must be erased and then the A/C compressor w...