A/C Controls

A single-zone HVAC system is available on all JR series vehicles.

MANUAL TEMPERATURE CONTROL

HVAC CONTROL
The HVAC system maintains incoming air temperature, airflow, fan speed, and fresh air intake for the entire vehicle from the instrument panel mounted AC - Heater Control. The full range of temperature that the system can produce in any mode for the entire vehicle is available by positioning the blend Control to the desired range.

AIR INTAKE
When the fresh-air door is open, outside air is drawn into the HVAC housing through the cowl opening at the base of the windshield. When the fresh-air door is closed, recirculated air is drawn in to the HVAC housing from under the instrument panel.

AIR DISTRIBUTION
The HVAC unit has four fully adjustable instrument panel outlets. Side-window demister outlets in the instrument panel eliminate the need for door ducts and door-to-instrument panel seals. A single, central mounted outlet delivers air for defrosting the windshield. Two ducts, one on each side of the center console underneath the instrument panel, provide airflow to the driver floor area and the front seat passenger floor area.

A/C-HEATER CONTROL, SWITCH OPERATION

BLOWER SWITCH
The rotary Blower Switch has five positions, Off, Low, M1, M2, and High. Rotating the Blower Switch results in the A/C - Heater Control providing direct blower motor activation, change in blower speed, and blower motor deactivation respectively. The Blower Switch must be in any of the four on positions to request A/C, and also to have the A/C - Heater Control send a signal to the Body Control Module to signal the door actuators to change door position.

MODE SWITCH
The rotary Mode Switch has a total of eight positions. The first three, for A/C request, include Recirc/Bi-level, Panel, and Bi-level. The remaining five positions, for Heat request, include Panel, Bi-level, Floor, Floor/Defrost, and Defrost. The Floor/Defrost position and the Defrost position also provided an A/C request.

MODE SWITCH, A/C REQUEST
Provided that the Blower Switch is in any of the four on positions, rotating the Mode Switch to any of the three A/C request positions, the Floor/Defrost position, or the Defrost position, will result in the A/C - Heater Control sending a signal to the BCM to send a message to the PCM to provide A/C compressor clutch activation. However, the BCM will only provide this request if EVAP function is found acceptable.

MODE SWITCH, MODE DOOR POSITION CHANGE REQUEST
Provided that the Blower Switch is in any of the four on positions, rotating the Mode Switch will result in the A/C - Heater Control sending a signal to the BCM to signal the actuator to move the mode door. A potentiometer, inside the Mode Door Actuator, and feedback circuits provide the BCM with door position information.

MODE SWITCH, FRESH-AIR DOOR POSITION CHANGE REQUEST
Provided that the Blower Switch is in any of the four on positions, rotating the Mode Switch to the Recirc position will result in the A/C - Heater Control sending a signal to the BCM to signal the actuator to close the fresh-air door. While rotating the mode Switch to any other position results in the A/C - Heater Control sending a signal to the BCM to signal the actuator to open the fresh-air door. When the Blower Switch is off, the fresh-air door closes to prevent outside air from entering the passenger compartment.

BLEND SWITCH
The rotary Blend Switch has multiple detents to control the full range of temperature that the system can produce in any mode. Provided that the Blower Switch is an any of the four on positions, rotating the Blend Switch will result in the A/C - Heater Control sending a signal to the BCM to signal the actuator to move the blend door. A potentiometer, inside the Blend Door Actuator, and feedback circuits provide the BCM with door position information.

REAR WINDOW DEFOGGER SWITCH
The Rear Window Defogger Switch is a momentary contact switch. Toggling the switch results in the A/C - Heater Control sending a signal to the BCM to provide rear window defogger activation or deactivation respectively. The switch LED illuminates when the switch is on.

DIAGNOSTIC TROUBLE CODES
All HVAC Diagnostic Trouble Codes are stored in the Body Control Module. Stored DTCs indicate that a problem has occurred in the HVAC system, and may still be present. To verify a problem is still present in the HVAC system, use the DRBIII(R) to erase all stored BCM DTCs. After erasing the DTC(s), use the DRBIII(R) to see if the DTC(s) reappear. If necessary, actuate the A/C - Heater Control switches with the ignition on and with the engine running while monitoring the DRBIII(R) to see if the DTC(s) reappear.