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 A/C system to determine when the A/C Compressor Clutch should be turned on. The PCM sends a signal through the Power Distribution Center (PDC) to activate the A/C Clutch Relay. The A/C Clutch Relay supplies 12 Volts to the A/C Compressor Clutch which has a dedicated ground circuit. You will not receive a MIL lamp for this fault, but the customer may complain of poor A/C performance.