GM Service Manual Online
For 1990-2009 cars only
Table 1: Heating and Air Conditioning
Table 2: Rear Auxiliary Climate Module
Table 3: Powertrain Control Module

Heating and Air Conditioning

Scan Tool Output Control

Additional Menu Selection(s)

Description

A/C Permission

Special Functions/Output Control/Miscellaneous Tests

When you select ON, the HVAC control module changes the state of the A/C Permission parameter to Granted and transmits a clutch enable message to the PCM over the class 2 serial data circuit. The A/C compressor clutch engages and remains engaged until you select OFF. When you select OFF, the HVAC control module changes the state of the A/C Permission parameter to Withheld and transmits a clutch disable message to the PCM over the class 2 serial data circuit.

Air Inlet Door

Special Functions/Output Control/Motor/Actuator Tests

When you select ON, the HVAC control module commands the recirculation actuator toward the maximum door position. The actuator moves the door to the recirculation position. When you select OFF, the HVAC control module commands the recirculation actuator toward the minimum door position. The actuator moves the door to the outside air position.

Blower Motor

Special Functions/Output Control/Motor/Actuator Tests

When you select ON, the HVAC control module commands the blower motor to maximum speed. The blower motor operates at maximum speed until you select OFF. The HVAC control module must be in the ON state before selecting the output control.

HVAC Actuator Recal.

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When you select RESET, the HVAC control module recalibrates the maximum and minimum door positions of each HVAC door. The ambient air temperature display is set to the current value of the Outside Air Temp. Raw parameter.

Inside Air Temperature Fan

Motor/Actuator Tests

When you select OFF, the HVAC control module commands the inside air temperature fan OFF. The fan remains OFF until you select ON. The normal state of the inside air temperature fan is ON.

Instant OAT Update

Special Functions/Output Control/Motor/Miscellaneous Tests

The scan tool displays Commanded State: None or On. This function updates the HVAC control module outside air temperature input to the current raw value.

Left Mix Motor

Special Functions/Output Control/Motor/Actuator Tests

When you select ON, the HVAC control module commands the left air temperature actuator toward the maximum door position. The actuator moves the door to the full hot position. When you select OFF, the HVAC control module commands the left air temperature actuator toward the minimum door position. The actuator moves the door to the full cold position.

Mode 1 Door Position

Special Functions/Output Control/Motor/Actuator Tests

When you select ON, the HVAC control module commands the mode actuator toward the maximum door position. The actuator moves the door to the panel position. When you select OFF, the HVAC control module commands the mode actuator toward the minimum door position. The actuator moves the door to the floor position.

Right Mix Motor

Special Functions/Output Control/Motor/Actuator Tests

When you select ON, the HVAC control module commands the right air temperature actuator toward the maximum door position. The actuator moves the door to the full cold position. When you select OFF, the HVAC control module commands the right air temperature actuator toward the minimum door position. The actuator moves the door to the full hot position.

Rear Auxiliary Climate Module

Scan Tool Output Control

Additional Menu Selection(s)

Description

Air Temperature

Special Functions/Output Control/Actuators

When you select ON, the auxiliary HVAC control module commands the auxiliary air temperature actuator toward the maximum door position. The actuator moves the door to the full hot position. When you select OFF, the auxiliary HVAC control module commands the auxiliary air temperature actuator toward the minimum door position. The actuator moves the door to the full cold position.

Blower Motor Test

Special Functions/Output Control/Blower Motor

When you select ON, the auxiliary HVAC control module commands the auxiliary blower motor to maximum speed. The auxiliary blower motor operates at maximum speed until you select OFF.

Calibrate HVAC Module

Special Functions/Miscellaneous Tests

When you select RESET, the auxiliary HVAC control module recalibrates the maximum and minimum door positions of each auxiliary HVAC door.

Inside Air Temp Sensor Fan

Special Functions/Output Control/Sensors

When you select ON, the auxiliary HVAC control module turns on the internal fan of the auxiliary inside air temperature sensor assembly. When you select OFF, the auxiliary HVAC control module disables the output.

Mode

Special Functions/Output Control/Actuators

When you select ON, the auxiliary HVAC control module commands the auxiliary mode actuator toward the maximum door position. The actuator moves the door to the upper position. When you select OFF, the auxiliary HVAC control module commands the auxiliary mode actuator toward the minimum door position. The actuator moves the door to the lower position.

Powertrain Control Module

Scan Tool Output Control

Additional Menu Selection(s)

Description

A/C Relay

Engine Output Controls

The engine must be running and the PCM must receive an A/C request from the HVAC control module in order to enable the output control. The PCM de-energizes the A/C compressor clutch relay when you select OFF. The relay remains de-energized until you select ON.