A/C Clutch: Notes

A 12-volt signal is supplied to the A/C request input of the PCM when the A/C is selected through the A/C control switch.

The A/C compressor clutch relay is controlled through the PCM. This allows the PCM to modify the idle air control position prior to the A/C clutch engagement for better idle quality. If the engine operating conditions are within their specified calibrated acceptable ranges, the PCM will enable the A/C compressor relay. This is done by providing a ground path for the A/C relay coil within the PCM. When the A/C compressor relay is enabled, battery voltage is supplied to the compressor clutch coil.

The PCM will enable the A/C compressor clutch whenever the engine is running and the A/C has been requested. The PCM will not enable the A/C compressor clutch if any of the following conditions are met:

All Models Except Rodeo & Rodeo Sport 2.2L

• The throttle is greater than 90 percent.
• The engine speed is greater than 6315 RPM.
• The ECT is greater than 246°F (119°C).
NOTE: Except Rodeo & Rodeo Sport 2.2L.
• The IAT is less than 41°F (5°C).
• The throttle is more than 80 percent open.

The A/C compressor operation is controlled by the Powertrain Control Module (PCM) for the following reasons:

• It improves idle quality during compressor clutch engagement.
• It improves Wide Open Throttle (WOT) performance.
• It provides A/C compressor protection from operation with incorrect refrigerant pressures.

The A/C system consists of the following components:

• The A/C control head.
• The A/C refrigerant pressure switches.
• The A/C compressor clutch.
• The PCM.