Module, A/C And Heater: Operation: Operation

WARNING: This page is about a different car, the 2012 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

The A/C heater module utilizes integrated circuitry and information carried over the Controller Area Network (CAN) data bus to monitor many sensors and switch inputs throughout the vehicle. In response to those inputs, the internal circuitry and programming of the A/C heater module allows it to control electronic functions and features of the heating and A/C system.

Some of the inputs received by the A/C heater module over the CAN bus are as follows:

A/C Request
Ambient Air Temperature
Electric Back Light (EBL) Request
Electrical System Voltage
Engine Coolant Temperature
Engine Speed
Humidity, Windshield Glass Temperature and Dewpoint (ATC only)
Refrigerant Pressure
Vehicle Identification Number
Vehicle Odometer

Some of the messages broadcasted by the A/C heater module on the CAN bus are as follows:

A/C Clutch Engage
Auto Headlamp Signal
EBL Status

The A/C heater module receives the following information over hardwired circuits:

Auto Headlamp Signal
Evaporator Temperature
Interior Air Temperature
Left and Right Sun Load

The A/C heater module monitors and controls the following over hardwired circuits:

Driver and Passenger Blend Door Positions
Blower Motor Speed
Mode Door Position
Recirculation Door Position

The A/C heater module is diagnosed using a scan tool. Prior to replacing an A/C heater module, run the calibration procedure to verify that the concern is not an air door calibration issue. Refer to STANDARD PROCEDURE .

The A/C heater module cannot be adjusted or repaired and must be replaced if inoperative or damaged.