GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 1998 🢒 Grand Prix 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 HVAC Air Delivery System Check

Action

Normal Results¹

    • Start the engine.
    • Press the heater-A/C control OFF button.
    • The outside temperature is displayed.
    • The blower does not run.

    • Press the AUTO button.
    • Turn the temperature knob until the temperature displays 15°C (60°F).
    • The blower runs at maximum speed.
    • The air flows from the panel outlets.
    • The A/C illuminates.
    • The engine idle speed increases.
    • The compressor turns ON.
    • The air flow becomes cold.
    • The engine coolant fan may operate.

  • Turn the fan control knob to LOW SPEED.
    • Turn the knob to decrease the blower speed.
    • The blower speed is displayed.
    • The blower operates at speed attained when the knob was released.

  • Turn the fan control knob to HIGH SPEED.
    • Turn the knob to increase the blower speed.
    • The blower speed is displayed.
    • The blower operates at speed attained when the knob was released.
  • Press the ECON button.
    • The engine idle speed decreases.
    • The compressor turns off.
    • The air flows from the panel outlets.
    • The air flow may start to warm.
    • Press the AUTO button.
    • Turn the temperature knob until the temperature displays 32°C (90°F).
    • The air flows from the floor outlets.
    • The air flow becomes warm.
  • Turn the temperature knob until the temperature displays 24°C (75°F).
    • The temperature display drops one degree at a time, stops at 24°C (75°F).
    • The blower speed reduces as the temperature approaches 24°C (75°F).
    • The A/C system maintains the temperature at approximately 24°C (75°F).
    • The air flows from the instrument panel and floor outlets when the temperature is near 24°C (75°F) when the control selector is put in the BI-LEVEL position.
  • Press the DEF button.
  • The air flows from the windshield outlets.
  • Press the DEFOG button.
  • The air flows from the panel, floor and windshield outlets.
  • Press the UPPER button.
  • The air flows from the panel outlets.
  • Press the LOWER button.
  • The air flows from the floor outlets.
  • Press the OFF button.
  • The blower turns off.