The heater and A/C control module may access 3 additional
purge modes when the following conditions exist:
| • | When the system is powered up, purge the system of stale air and/or
to redirect the air in order to avoid window fogging or other undesirable
conditions. |
| • | When the ignition is turned ON and the fan increase/decrease knob
is not in the OFF position, the heater and A/C control module will determine
if any of the undesirable conditions exist. |
The heater and A/C control module may select from one of the following
3 purge modes in order to eliminate the undesirable condition:
Normal Purge Mode
Moisture tends to accumulate in the heater and the A/C module assembly
after the engine has been turned off. When the engine is restarted and the
A/C system turns ON this moisture may be expelled from the windshield or
panel outlets and cause window fogging. The normal purge mode is bypassed
if the fan is in a manual selection.
Cold Purge Mode
In the cold weather, the moist breath air from the vehicle occupants
may condense on the windshield. On cold startup, the heater and A/C control
module checks for indications that this condition may occur. If this condition
occurs, the heater and A/C control module performs the following actions:
| • | Positions the doors to direct air out of the windshield outlets |
The heater and A/C control module then resumes normal system operation.
A/C Purge Mode
Moisture tends to accumulate in the heater and A/C control module assembly
after the engine has been turned off. When the engine is restarted and the
A/C system turns ON, this moisture may be expelled from the panel outlets
toward the front seat occupants.
During startup, the heater and heater and A/C control module inspects
for indications that this condition may occur. If this condition occurs, the
heater and A/C control module performs the following actions:
| • | Positions the A/C door to direct air toward the floor |
The heater and A/C control module then resumes normal system operation.
