Aspirator: Description and Operation

Cabin air is drawn through a grille (located near the steering column on the knee bolster) over a thermistor. Remotely mounted from the thermistor is the motorized aspirator with a rubber hose which connects both components.

The electrical resistance of the thermistor changes in response to variations in air temperature and converts this temperature rating into an electrical signal; the signal is used by the A/CCM to adjust the temperature, airflow and air distribution from the air conditioning unit.

Coolant Temperature Signal.
This signal is supplied to the A/CCM from the instrument cluster, the input being required to:
- Provide blower inhibit control , to avoid the system in heating mode delivering cold air when the coolant temperature is below 35 °C unless DEFROST is selected.
- To progressively increase the fan speed up to maximum blower speed during warm up control. To assist in the control of the outlet temperature.
- To avoid possible pump or valve damage caused by ice particles in the coolant.