Questions and Answers

300M A/C Not Very Cold Q. I have a 1999 Chrysler 300M and the A/C does not blow cold air. The A/C was recently serviced (the system was evacuated and 2.7 pounds of refrigerant was added), but the system still does not perform properly. The A/C technician did not report any leaks in the system.

Can you advise me if there are any other steps to take to check the performance of the system before I have the compressor replaced?

Thank You,
Vernon

A. A/C systems are really tough to diagnose in this venue. To really find out if you need a compressor you need to hook up a set of A/C gauges and see what the pressures are. Assuming the system has the proper charge, if you have a low pressure reading on the high side, that would indicate a bad A/C compressor.

I would have Chrysler look at it. There was a TSB, number 24-009-01 issued Aug. 3, 2001. Basically it recalibrates the HVAC control unit. You can do it yourself and see if it helps. The repair procedure from the bulletin is:

With vehicle at room temperature (50 to 800F.), remove fuse 19 from the junction block (M-1 circuit) for five minutes to erase DTCs. Replace fuse and start vehicle to recalibrate HVAC system. Operate vehicle and A/C heater system to verify that symptoms and/or DTCs are gone. If dithering/tapping noise or Blend Stall/Feedback DTCs re-occur, additional diagnosis will be required.

Additional Information provided courtesy of ALLDATA