GM Service Manual Online
For 1990-2009 cars only
 

Control Settings

System Response

A/C SW

Mode Lever

Temp Control

Fan Switch

Blower Speed

A/C Outlet

Heater Outlets

Defrost Outlets

See Remark

Rear Seat Heat Duct

OFF

OFF

COLD

LOW

Off

No Air Flow

No Air Flow

No Air Flow

-

None

OFF

MAX

COLD

LOW

Low

Air Flow

Min Air Flow

No Air Flow

A, I, K

Min

OFF

MAX

COLD

LOW to HIGH

Low to High

Air Flow

Min Air Flow

No Air Flow

B, F

Min

OFF

VENT

COLD

HIGH to M2

High to M2

Air Flow

Min Air Flow

No Air Flow

A, C, G

Min

OFF

BI-LEVEL

COLD

M2

M2

Air Flow

Air Flow

No Air Flow

A

Min

OFF

HEATER

HOT

HIGH

High

No Air Flow

Air Flow

No Air Flow

A, D, E

Air Flow

OFF

BLEND

HOT

HIGH

High

No Air Flow

Air Flow

Air Flow

A, H

Min

OFF

DEF

HOT

HIGH

High

No Air Flow

Min Air Flow

Air Flow

A, H, I

Min

ON

VENT

COLD

HIGH

High

Air Flow

No Air Flow

No Air Flow

J

None

REMARK A: Engagement of the detent must be felt in each mode.

REMARK B: Progressive blower speed increase must occur between LO, M1, M2 and HI

REMARK C: Listen for the reduction of air noise.

REMARK D: Inspect the temperature level for full travel (Hot or Cold).

REMARK E: Inspect for air flow at the side window defogger outlets

REMARK F: At room temperature the air from the center A/C outlets should feel cold with the blower speed on HIGH.

REMARK G: The temperature from the vent outlets should be the same as the temperature outside of the vehicle.

REMARK H: Temperature from the defroster outlets should be above the temperature outside the vehicle.

REMARK I: Slight engine flare should be noted as the A/C clutch engages and disengages.

REMARK J: Barrels and vanes must hold position with the fan on HIGH.

REMARK K: Engage the REC button and an increase of air flow out of the A/C outlets must occur.

The vehicle A/C must be on for a minimum of 90 seconds prior to performing the tests.

Perform each step of the functional tests with the following conditions in place:

    • The windows are up.
    • The doors are closed.