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

Fan Speed (PWM)

Fan Speed

The HVAC control module will command the blower motor Off, Low, Medium or High.

Mix Actuator

Actuator Tests

When you select ON, the HVAC control module commands the Mix Actuator to full Hot. When you select Off, the HVAC control module commands the Mix Actuator to full Cold.

Mode Actuator

Actuator Tests

When you select ON, the HVAC control module commands the Mode Actuator to the Vent position. When you select Off, the HVAC control module commands the Mode Actuator to the Defrost position.

Recirculation Actuator

Actuator Tests

The HVAC control module commands the air inlet door to the recirculation position when you select ON. The HVAC control module commands the air inlet door to the ambient air position when you select OFF.

Lamp Test

Actuator Tests

The HVAC control module commands the back light on the LCD display On and Off.

LCD Display

Actuator Tests

The HVAC control module commands all segments of the LCD display On and Off.

PCM Scan Tool Output Controls

Scan Tool Output Control

Additional Menu Selection(s)

Description

A/C Relay

Engine Output Controls

The scan tool displays ON or OFF selections. This command allows you to turn the A/C relay On or Off. The A/C clutch cannot be commanded On unless the engine is running and the A/C switch is controlled OFF. When the A/C relay is commanded On, the A/C compressor clutch should be engaged.