Theory Of Operation
WARNING: This page is about a different car, the 2013 RAM 3500 HD and 2013 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) receives various information from the operator controls and engine sensor inputs to determine when the A/C Compressor Clutch should be turned on. The A/C Pressure Sensor information is a direct input to the PCM. You will not receive a MIL lamp for this fault, but the customer may complain of poor A/C performance.