Air Distribution System
Air utilized by the HVAC system is drawn into the blower module through the air inlet assembly at the base of the windshield and routed through the blower. The blower forces the air through the HVAC filter and then through the evaporator core where it is dehumidified and cooled. The air is then heated as required by passing through or around the heater core. Now conditioned, the air is directed by air valves in the A/C module to the outlets in the instrument panel, to the heater outlets at the floor, front and rear, or to the defroster outlets, depending upon the mode selected by the driver.
HVAC Air Filters
The filters are located in the HVAC module in front of the evaporator core. These filters will filter fresh air coming into the vehicle and air that is recirculated within the vehicle. The filter housing is located in the front left corner of the HVAC Module near the accelerator pedal. The filters are accessed by pulling down on the filter access cover.
The HVAC air filter assembly consists of three separate interlocking elements. Each of these filters are identical in appearance and operation.
The filters are removed and installed one at a time. The filters may be bent slightly which will aid in the installation and removal. Each filter element has a tab at the lower left corner to assist in the installation and removal. The tab on the filter is channeled which helps to align the interlocking feature of the filters.
The filters are to be changed every 12 months or 12,000 miles whichever comes first. These filters may require more frequent change intervals depending on driving conditions.
Air Inlet Assembly
The air inlet assembly provides outside (fresh) or inside (recirculated) air to the blower depending on the mode selected by the driver. The inlet air is varied by an actuator that is controlled by the heater and A/C programmer.
Blower Motor
The blower consists of a permanent magnet type motor and squirrel cage type fan. The blower operates at various speeds determined by the heater and A/C programmer.
The blower motor is cooled by having a small portion of blower output air recirculated through the motor housing through a rubber tube.
The blower is located in the passenger compartment near the right side of the HVAC module.
Mode Air Valve
After passing through the evaporator core the now cooled and dehydrated air will pass, all or in part, through the heater core. This will establish the desired air temperature as requested by the driver.
Once conditioned to the correct temperature the air enters the air distribution chamber. Valves in the air distribution chamber are positioned by the heater and A/C programmer through the use of the mode actuator. By varying the position of the mode valve door, the air distribution chamber is able to direct air flow to the floor, windshield or the upper ducts. Air always passes through the rear floor duct.
Ducts and Outlets
The ducting is the network of tubing used to get conditioned air from the HVAC module to the instrument panel and rear seat outlets. There are four major ducts that are attached to the air distribution chamber.
1. Cross Car Ducts.
2. Rear Seat Duct.
3. Heater Duct.
4. Defrost and Side Window Duct.
The cross car ducts are attached to the instrument panel carrier. It receives air from the distribution chamber.
The rear seat duct receives air from the bottom of the distribution chamber and delivers it through two outlets at the rear of the front seat center arm rest or console.
The heater ducts are part of the insulator panels located on either side of the vehicle and distribute heater air to the front occupants.
The defroster and side window ducts are attached to the top of the HVAC module and distribute the air to the windshield and the front side windows.