GM Service Manual Online
For 1990-2009 cars only
Table 1: Heating and Air Conditioning
Table 2: Rear HVAC/RSA (Body Type VIN 6)
Table 3: PCM

Heating and Air Conditioning

Scan Tool Output Control

Additional Menu Selection(s)

Description

A/C Permission

Special Functions/Output Control/Miscellaneous Test

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.

Special Functions

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

Special Functions/Output Control/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/Miscellaneous Test

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.

Mode 2 Door Position

Special Functions/Output Control/Motor/Actuator Tests

When you select ON, the HVAC control module commands the defroster actuator toward the maximum door position. The actuator moves the door to the defrost position. When you select OFF, the HVAC control module commands the defroster actuator toward the minimum door position. The actuator moves the door in the opposite direction of the defrost 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 HVAC/RSA (Body Type VIN 6)

Scan Tool Output Control

Additional Menu Selection(s)

Description

Air Mix Door

Special Functions

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

Special Functions

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. The auxiliary HVAC control module must be in the ON state before selecting the output control.

Console Door Position

Special Functions

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

HVAC Actuator Recal.

Special Functions

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

Mode Door Position

Special Functions

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.

Water Valve

Special Functions

When you select ON, the auxiliary HVAC control module sends a class 2 serial data message to the HVAC control module to command the coolant bypass valve to the closed position. The coolant bypass valve solenoid is engaged and vacuum is applied to the coolant valve. The valve will close. When you select OFF, the auxiliary HVAC control module sends a class 2 serial data message to the HVAC control module to command the coolant bypass valve to the open position. The coolant bypass valve solenoid is disengaged and vacuum is removed from the coolant valve. The valve will open.

PCM

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.