Circuit Operation

COMPRESSOR CONTROLS

The Compressor for the Air Conditioning System is driven by the engine by means of a belt drive and the AC Compressor Clutch. The Clutch allows the Compressor to be disengaged when Air Conditioning is not required. Power to the AC Compressor Clutch is supplied by the HTR-AC Fuse.

AC Compressor Clutch Diode
The AC Compressor Clutch Diode is connected across the terminals of the AC Compressor Clutch. Whenever the clutch is de-energized, the magnetic field around it collapses, generating an induced voltage in the clutch coil. The Diode provides a path for the current resulting from the induced voltage so that other circuit components are not damaged.

Evaporator Pressure Control Switch
The AC Compressor for these engines is controlled the same way as the 2.5L VIN E, except that an Evaporator Pressure Control Switch is used in place of the Low Pressure Switch. Also, these engines do not use a Power Steering Pressure Switch. On these engines, if the AC system pressure drops below 172 kPa (25 psi), the Evaporator Pressure Control Switch opens stopping current flow to the AC Compressor. When the AC system pressure rises to 310 kPa (45 psi), the switch closes and current again flows to the AC Compressor.