Air Distribution

When you press the mode switches, a signal is sent from the HVAC control module to the mode. actuator through the mode door control circuit. When the logic inside the actuator receives the signal, the mode actuator moves into the desired position.

The rear fuse block provides power to the mode actuator through the ignition 3 voltage circuit. Ground is provided by the low reference circuit, the HVAC control module and ground circuits.

The HVAC control module receives power from the rear fuse block on the ignition 3 voltage circuit and battery positive voltage circuit. The ground circuits provides ground for the module.

The mode actuator is a DC motor, 0 volts drives the actuator in one direction while 12 volts moves the actuator in the opposite direction. A 12 volt signal is sent out over the mode door control circuit, from the HVAC control module, to the mode actuator. When a mode setting is selected, the logic inside the actuator is used to determine the mode door position signals value. The motor moves the mode door to the desired position. When servicing the actuators, make sure you use the correct service part number. There are specific parts for the left and right side of the HVAC module. Using the wrong part will effect mode operation.

Vent Mode
When the driver presses the VENT switch, outside air is brought into the vehicle and the A/C compressor clutch is turned OFF. The blower motor will be activated. Air is delivered through the instrument panel vents. VENT is not available when FRONT DEF is selected. The VENT LED will flash to indicate that VENT is not available.

Heater Mode
When the driver presses the HTR switch, outside air is brought into the vehicle and the A/C compressor clutch is turned OFF. The blower motor will be activated. Recirculation mode is available. Air is delivered mainly through the floor outlets but some air will come out through the windshield vents and side window outlets.

Mix-Blend Mode
When the driver presses the MIX-BLEND switch, outside air is brought into the vehicle and the A/C compressor clutch is turned ON. The blower motor will be activated. Recirculation mode is available. Air is delivered through the floor and windshield outlets.

Front Defrost
When the driver presses the FRONT DEF switch, outside air is brought into the vehicle and the A/C compressor clutch is turned ON. The blower motor will be activated. Air is delivered through the windshield outlets. VENT and RECIRC are not available in these modes. The VENT or RECIRC LED will flash accordingly to indicate that those modes are not available.

Max Mode
When the driver presses the MAX switch, recirculated air is cycled through the vehicle and the A/C compressor clutch is turned ON. The blower motor will be activated. Air is delivered through the instrument panel outlets. The recirculation LED will not light, but the system will be in recirculation mode.

Norm Mode
When the driver presses the MODE switch, outside air is brought into the vehicle and the A/C compressor clutch is turned ON. The blower motor will be activated. Recirculation mode is available. Air is delivered through the instrument panel outlets.

Bi-level Mode
When the driver presses the BI-LEV switch, outside air is brought into the vehicle and the A/C compressor clutch is turned ON. The blower motor will be activated. Recirculation mode is available. Air is delivered through the instrument panel and floor outlets.