The PCM Controlled A/C system consists of the following:
| • | The HVAC control assembly. |
| • | A/C refrigerant high and low pressure switches. |
| • | A/C high and low temperature sensors. |
When the HVAC control assembly is placed in the A/C mode, a request
signal is sent to the PCM. The PCM will then energize the A/C clutch relay,
unless abnormally high or low A/C pressure is detected by the A/C refrigerant
pressure switches or certain DTC's are set. The PCM also monitors the A/C
low temperature sensors to cycle the A/C clutch ON and OFF. If the PCM detects
an A/C evaporator temperature less than 2°C (36°F), the A/C clutch
will be prohibited from being enabled. The PCM will also energize the cooling
fans ON when A/C is requested. Refer to Electric Cooling Fan(s) in Engine
Cooling. The A/C control relay is controlled by the PCM so that the PCM can
increase idle speed before turning ON the clutch or disable the clutch when
high engine coolant temperature is detected or high engine RPM is detected.
