GMC chervolet camaro 1999 Service Manual page 211

1-120 HVAC.System - Manual
282925
HVAC
Installation Procedure
1. Install the vacuum harness.
2. Connect the vacuum hoses to the actuators.
3. Install the 1/P carrier. Refer to IP Ca"ier
Replacement.
Description and Operation
A/C System Description
The HVAC system delivers air that has been heated
or cooled and dehumidified for occupant comfort.
The HVAC system also provides the following features:
• Ventilation
(
• Windshield defrosting (
• Side window defogging
During most operating condition, the blower motor
draws the outside air through the heater and air
conditioning module. The forward movement of the
vehicle forces additional air into the vehicle. The
following actions occur in the evaporator core when
the compressor is on:
• The air is filtered
• The air is dehumidified
• The air is cooled to about 2°c (35°F)
Some of the air then passes through the heater core
where the flow of hot coolant reheats the air.
Depending on the temperature door position, the
heated air is mixed with cold air from the evaporator
before the air enters into the passenger compartment.
The air enters the passenger compartment through
the upper, lower, or defroster outlets. This provides
positive air flow even if the windows are closed.
When the Recirc mode is selected, most of the air
entering the evaporator and heater core module
is recirculated from the passenger compartment.
Recirculated air is most likely cooler and dryer than
outside air in very hot weather.