Powertrain Control Module (PCM)

The PCM indirectly controls power to the A/C clutch. When the PCM senses ground through the mode selector switch, it grounds the coil circuit of the A/C relay. Contacts in the A/C relay close, allowing power to the A/C clutch. The PCM shuts off the A/C clutch during such conditions as engine starting, high engine speed, heavy acceleration, high engine coolant temperature, and low engine idle.