Automatic Modes

The automatic HVAC system changes or maintains the interior temperature of the vehicle by controlling the following functions:
^ The A/C compressor clutch
^ The blower motor
^ The air temperature
^ The mode and recirculation actuators

For fully automatic operation, both the blower and mode switches must be in the AUTO position. Blower speeds will change automatically based on inputs to the IPM. The IPM always returns to the last settings after an ignition cycle. If equipped, the IPM returns to the last settings of the driver by pressing the UNLOCK button on the remote keyless entry fob and placing the ignition in RUN, or by using the MEMORY button on the driver's door.

Moisture tends to accumulate in the HVAC module assembly after the engine has been shut off. The IPM will purge the HVAC module of stale air and moisture in order to prevent window fogging. The mode actuator will move to the floor mode and run the low speed blower for 10 seconds in order to purge out the air and moisture. Purge mode can be bypassed if any manual modes are selected.

In cold temperatures, the automatic HVAC system will provide heat in the most efficient manner. At initial vehicle start up, the blower motor is not turned ON until the coolant temperature reaches a predetermined level. If the coolant does not warm up within that preset time, the blower is activated. You can override this delay by pressing the FAN, AIR FLOW or FRONT DEFROST button. On cold engine start-up, in cold weather, the IPM moves the mode outlets to the windshield and operates the blower. In order to warm the interior quickly, use the maximum heat mode with the blower set at maximum speed, the mode on floor, the air temperature actuator is at full hot, and the ambient air is being drawn in. The vehicle operator can select the extreme warm setting of 30°C (90°F), but the system will not warm the vehicle any faster. Once the desired temperature is reached, the IPM automatically adjusts the blower motor, the mode, and the temperature.

In warm temperatures, the automatic HVAC system will provide A/C in the most efficient manner. On vehicle start up, the IPM will monitor for moisture in the HVAC module. In order to avoid blowing moisture out at the driver, the IPM moves the mode door toward the floor and instrument panel outlets and runs the blower at medium speed for 3 seconds. You can bypass this purge mode by selecting any manual modes. In order to cool the interior quickly, maximum cool mode is used with the blower set at maximum speed, the air temperature actuator is set to full cold, and the recirculation actuator is drawing air from inside the vehicle. The vehicle operator can select the extreme cool setting of 16°C (60°F), but the system will not cool the vehicle any faster. Once the desired temperature is reached, the IPM automatically adjusts the blower motor, the mode and the temperature.