A/C System

NOTE: The following information is intended to be used in conjunction with the electrical diagrams.

CIRCUIT OPERATION
When the A/C-Heater control switch is moved to an A/C position or defrost position, and the A/C low pressure and high pressure switches are closed, the Powertrain Control Module (PCM) receives an A/C request signal on circuit C20. Circuit C20 connects to cavity 27 of the PCM.

After receiving the A/C request signal, the PCM supplies ground for the coil side of the A/C clutch relay on circuit C13. Circuit C13 connects to cavity 34 of the PCM. Circuit A21 supplies battery voltage to the coil side of the relay. Circuit C26 from fuse B in the Power Distribution Center (PDC) supplies voltage to the contact side of the relay.

When the PCM grounds the A/C compressor clutch relay, the contacts close and connect circuits C26 and C3. Circuit C3 supplies voltage to the A/C compressor clutch. Ground for the compressor clutch is provided on circuit Z1 which terminates at the left fender side shield.

The A/C compressor clutch connector has a built-in diode. The diode controls the induced voltage that results from the magnetic field collapsing when the clutch disengages. The diode provides a current path to protect other components and systems.