Heating And Air Conditioning
DESCRIPTION
The Tri-Zone and Quad-Zone Automatic Temperature Control (ATC) Heating, Ventilation and Air Conditioning (HVAC) systems are comprised of the following subsystems; refer to the subsystems for specific information.
| 1. | Refer to: PLUMBING, FRONT, DESCRIPTION AND OPERATION (Orange) |
| 2. | Refer to: FRONT SYSTEM CONTROLS - DESCRIPTION AND OPERATION (Red) |
| 3. | Refer to: FRONT AIR DISTRIBUTION - DESCRIPTION AND OPERATION (Blue) |
| 4. | Refer to: REAR AIR DISTRIBUTION - DESCRIPTION AND OPERATION (Green) |
| 5. | Refer to: PLUMBING, REAR, DESCRIPTION AND OPERATION (Black) |
| 6. | Refer to: REAR SYSTEM CONTROLS - DESCRIPTION AND OPERATION (Purple) |
OPERATION
With the automatic HVAC system, the operator can choose either automatic or manual operation. During automatic operation, the operator simply sets a target temperature. The HVAC module determines the best combination of A/C compressor operation, blend door position, outlet air direction, speed to control passenger compartment humidity and reach the target temperature. During manual operation, the operator can select A/C operation, air flow speed, air flow outlet location, and choose either fresh or recirculated air.
The HVAC system on all models include a front dual zone subsystem and either a rear single zone or dual zone subsystem, depending on whether the system is a Tri-Zone or Quad-Zone system. Both the Tri-Zone and Quad-Zone front systems have four actuators: one mode door, one recirculation door and two temperature blend door actuators, on the front HVAC housing to control the mode, recirculation and temperature blend doors. The rear Quad-Zone system includes five actuators: two temperature blend door actuators on the rear HVAC housing for right and left rear temperature control and three mode door actuators. The rear Tri-Zone system includes four actuators: a single temperature blend door actuator and three mode door actuators.
The front and rear HVAC modules are connected to the Controller Area Network - Interior High Speed (CAN-IHS) data bus and receive the information of the humidity/sun/light and ambient temperature sensors via CAN from the Body Control Module. The system manages air recirculation, distribution and temperature using the actuators with a potentiometer for opening, closing and regulating the intermediate positions via electrical commands. The HVAC modules control the mixing temperatures using data from the temperature sensors located in the front and rear HVAC housings. The system manages the air temperature request by also monitoring solar radiation through a combination Humidity Rain Light Sensor Module (HRLSM) that measures the amount of radiant light coming in the vehicle and the amount of humidity inside the vehicle, mounted to the windshield, and interior vehicle temperature from the in-car temperature sensor, located in the steering column opening cover. An A/C activation request from the user or a heated rear window activation request is sent to and activated by the BCM via CAN. The A/C request status and the actuator positions are stored in the HVAC module. The HVAC manages ON/OFF activation of the rear window defroster.
To maintain the performance level of the HVAC system, the engine cooling system must be properly maintained. The use of a bug screen is not recommended. Any obstructions in front of the radiator or A/C condenser will reduce the performance of the A/C and engine cooling systems. For information regarding the components that comprise the engine cooling system, and for more information before opening or attempting any service to the engine cooling system. Refer to: 3.0L [EFC] (HO) - COOLING SYSTEM, DESCRIPTION AND OPERATION and 3.0L [EFH] (SO) - COOLING SYSTEM, DESCRIPTION AND OPERATION .