GM Service Manual Online
For 1990-2009 cars only
Table 1: HVAC Control Module Scan Tool Output Controls
Table 2: PCM Scan Tool Output Controls

HVAC Control Module Scan Tool Output Controls

Scan Tool Output Control

Additional Menu Selection(s)

Description

A/C Permission

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

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

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 Recalibration

--

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.

Left Mix Motor

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 Door Position

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

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.

PCM Scan Tool Output Controls

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.