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

HVAC Control Module Scan Tool Data Parameters

Parameter

System State

Expected Value

Definition

Operating Conditions: Engine ON

A/C Refrigerant Pressure

--

Varies

The scan tool displays MPaG. This is the current refrigerant pressure.

Engine Coolant Temp.

--

Varies

The scan tool displays °C or °F. This is the current engine coolant temperature.

Evaporator Temp.

--

Varies

The scan tool displays °C or °F. This is the current evaporator temperature.

Outside Air Temp

--

Varies

The scan tool displays °C or °F. This is the current outside air temperature.

Outside Air Temp. Filtered

--

Varies

The scan tool displays °C or °F. This is the current filtered outside air temperature.

Pressure Regulator Sol.

--

Varies

The scan tool displays Amps. This is the current of the pressure regulator solenoid.

HVAC Control Module Scan Tool Output Controls

Scan Tool Output Control

Description

A/C Request

This command allows you to turn the A/C relay On and Off. When the A/C relay is commanded On, the A/C compressor clutch should be engaged.

Blower Motor

When On is selected, the HVAC control module commands the blower motor relay On and a command to increase or decrease air. When Off is selected, the HVAC control module commands the blower motor relay Off.