DTC P0645 A/C Clutch Relay Control Circuit: General Description

The A/C relay is activated if the A/C switch is ON while the blower is running and system operation is enabled the ECM/PCM. Power is then supplied to the A/C compressor electromagnetic clutch and A/C system is operated. The A/C compressor is switched out to prevent it running when full engine output is required or there is a risk of overheating. The ECM/PCM also inhibits compressor operation on starting to permit running conditions to stabilize.