ATC Module

ATC Module

The ATC (automatic temperature control) module is installed in the center of the fascia. An integral control panel contains push switches and rotary switches/knobs for system control inputs. Orange tell-tale LED (light emitting diode) s in the switches and switch surrounds illuminate to indicate the current settings of the system. The rotary temperature switch is graduated in degree Celsius, except on USA vehicles, where it is graduated in degree Fahrenheit.

An in-vehicle temperature sensor and associated electric fan are installed behind a grille in the control panel.

The ATC (automatic temperature control) module processes inputs from the control panel switches and system sensors, then outputs the appropriate signals to control the A/C (air conditioning) system. In addition to controlling the A/C (air conditioning) system, the ATC (automatic temperature control) module also controls the following:
^ The heated windshield and windshield wiper parking area heater (optional fit, not available on vehicles with infra red protection glass).
^ The windshield washer jet heaters.The HRW (heated rear window).
^ The front seat heaters.

Manual Control Panel







The switches on the manual control panel have the following functions:
^ Heated windshield Switch: Enabled only with the engine running. Pressing the switch energizes the heated windshield and the windshield wiper parking area heater for a set time period, until the switch is pressed again or until the engine stops, whichever occurs first. A LED (light emitting diode) above the switch is illuminated while the heaters are on.
^ LH and RH Seat Heater Switches: Activates the heater elements in the seat cushion and seat back at one of two heat levels. The first press of the switch energizes the heater elements at the higher heat setting and illuminates two LED (light emitting diode) in the switch. A second press of the switch sets the heater elements to the lower heat setting and extinguishes one of the LED (light emitting diode) s. A further press of the switch de-energizes the heater elements and extinguishes the second LED (light emitting diode). The seat heaters remain on until selected off or the ignition is switched off.
^ Temperature Switch: Adjusts the passenger compartment nominal temperature setting between 16 and 28 degrees C (60 and 84 degrees F). The temperature range is engraved on the switch surround (degree F for NAS, degree C for rest of world). A pointer on the switch indicates the selected temperature. In the minimum and maximum temperature positions, the temperature is set to maximum cooling or maximum heating respectively.
^ Blower Switch: For manual adjustment of blower speed. Up to seven LED (light emitting diode) s in the switch surround illuminate to indicate the selected blower speed.
^ Distribution Control Knob: For manual adjustment of air distribution. Includes AUTO setting where distribution doors are set to a nominal comfort position.
^ A/C Switch: Activates the A/C (air conditioning) compressor. Allows the A/C (air conditioning) compressor to be selected off for economy operation. A LED (light emitting diode) above the switch is illuminated when the A/C (air conditioning) compressor is selected on.
^ Recirculation Switch: For manual selection of fresh or recirculated air. A LED (light emitting diode) above the switch is illuminated when recirculated air is selected.
^ HRW Switch: Enabled only with the engine running. Pressing the switch energizes the HRW for a set time period, until the switch is pressed again or until the engine stops, whichever occurs first. A LED (light emitting diode) above the switch is illuminated while the heater is on.

Automatic System Control Panel







The switches on the automatic system control panel have the following functions:
^ Heated Windshield Switch: Energizes the heated windshield and the windshield wiper parking area heater for a set time period, until the switch is pressed again or until the engine stops, whichever occurs first. A LED (light emitting diode) above the switch is illuminated while the heaters are on.
^ LH and RH Seat Heater Switches: Activates the heater elements in the seat cushion and seat back at one of two heat levels. The first press of the switch energizes the heater elements at the higher heat setting and illuminates two LED (light emitting diode) s in the switch. A second press of the switch sets the heater elements to the lower heat setting and extinguishes one of the LED (light emitting diode) s. A further press of the switch de-energizes the heater elements and extinguishes the second LED (light emitting diode). The seat heaters remain on until selected off or the ignition is switched off.
^ LH and RH Temperature Switches: Adjusts the nominal temperature settings of the LH (left-hand) and RH (righthand) sides of the passenger compartment between 16 and 28 degrees C (60 and 84 degrees F). The temperature range is engraved on the switch surrounds. A pointer on each switch indicates the selected temperature. In the minimum and maximum temperature positions, the system operates at maximum cooling or maximum heating respectively.
^ Automatic Mode Switch: Activates the automatic modes for air volume and distribution and also activates the A/C (air conditioning) compressor. Separate LED (light emitting diode) s in the automatic mode switch illuminate when the blower and the distribution control doors are in automatic mode. Manually selecting the blower speed or a distribution switch extinguishes the related LED (light emitting diode).
^ Blower Switch: For manual adjustment of blower speed. Up to seven LED (light emitting diode) s in the switch surround illuminate to indicate the selected blower speed.
^ A/C Switch: Controls activation of the A/C (air conditioning) compressor. Allows the A/C (air conditioning) compressor to be selected off for economy operation. A LED (light emitting diode) above the switch is illuminated when the A/C (air conditioning) compressor is selected on.
^ Recirculation Switch: For manual or automatic selection of fresh or recirculated air. Two LED (light emitting diode) s above the switch illuminate to indicate the mode and position of the recirculation doors. The first press of the switch sets the recirculation doors to automatic mode and illuminates the LH (left-hand) LED (light emitting diode). A second press of the switch manually sets the recirculation doors to the recirculation position, extinguishes the LH (left-hand) LED (light emitting diode) and illuminates the RH (right-hand) LED (light emitting diode). A further press of the switch manually sets the recirculation doors to the fresh air position and extinguishes the RH (right-hand) LED (light emitting diode).
^ Maximum A/C Switch: For selection of maximum A/C (air conditioning) when the ignition is on or rest heating when the ignition is off. A LED (light emitting diode) above the switch is illuminated when maximum cooling or rest heating is selected.
^ Distribution Switches (Windshield, Face and Footwell): For manual selection of air distribution in any combination of windshield, face and footwell outlets. A LED (light emitting diode) above each switch illuminates when a selection is made.
^ Defrost Program Switch: Activates a program that automatically selects the heated windshield on, activates the A/C (air conditioning) compressor and changes the system settings to direct dry heat to the windshield. A LED (light emitting diode) above the switch is illuminated while the defrost program is active.
^ HRW Switch: Enabled only with the engine running. Pressing the switch energizes the HRW for a set time period, until the switch is pressed again or until the engine stops, whichever occurs first. A LED (light emitting diode) above the switch is illuminated while the heater is on.

Inputs and Outputs
Five electrical connectors provide the interface between the ATC (automatic temperature control) module and the vehicle/heater assembly wiring.

Both the manual and automatic systems receive ambient temperature, engine coolant temperature, engine speed and vehicle speed inputs in K bus messages from the instrument cluster. If the K bus messages are missing or faulty, the ATC (automatic temperature control) module adopts the following default values:
^ Ambient temperature = 0 degree C (32 degrees F).
^ Engine coolant temperature = 80 degrees C (176 degrees F).
^ Engine speed = 800 rev/min.
^ Vehicle speed = zero.

If a fault develops in the input from the temperature selector switch on the control panel, the ATC (automatic temperature control) module adopts a default value of 24 degrees C (75 degrees F).

ATC (automatic temperature control) Module Harness Connector C0249 Pin Details







ATC (automatic temperature control) Module Harness Connector C0923 Pin Details







ATC (automatic temperature control) Module Harness Connector C1629 Pin Details







ATC (automatic temperature control) Module Harness Connector C1630 Pin Details







ATC (automatic temperature control) Module Harness Connector C2295 Pin Details