GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

  1. Place the ignition switch in the ON position.
  2. Place the heater - A/C control mode selector in the VENT position.
  3. Place the blower control in a medium speed.

Air flows from the panel outlets.

Air Recirculation Always On

2

Place the heater - A/C control in the BI-LEVEL position.

    • Air flows from the panel and the floor outlets.
    • There is a slight air flow from the defrost outlets.

Instrument Panel Outlets Inoperative

3

Place the heater - A/C control in the HEATER position.

    • Air flows from the floor outlets.
    • There is a slight air flow from the defrost outlets.

Heater Air Inoperative

4

Place the heater - A/C control in the MAX position.

    • Air flows from the panel outlets.
    • Inside air is recirculated through the cooling system.

Air Recirculation Inoperative

5

Place the heater - A/C control in the DEFROST position.

    • Air flows from the defrost outlets.
    • There is a slight air flow from the floor outlets.

Defrost Air Inoperative