GM Service Manual Online
For 1990-2009 cars only
Table 1: Pontiac and Oldsmobile w/o Outside Recirculated Air Option
Table 2: Outside Recirculated Air Option (Oldsmobile Only)

Perform the Functional Test and the diagnostic tests in order to verify the following systems:

    • Air conditioning
    • Electrical
    • Vacuum
    • Refrigeration
  1. Operate the blower motor at all speeds with the mode lever in any position, and engage the compressor clutch. This will indicate that the electrical circuits and the vacuum circuits are functioning properly.
  2. With your hand, feel the temperature of the evaporator inlet pipe and the accumulator surface of an operating system. The system will be properly charged if these temperatures feel the same.
  3. Operate the heater and A/C control selector (mode) lever, which distributes air from the appropriate outlets. Verify that the lever operates correctly and smoothly.

Pontiac and Oldsmobile w/o Outside Recirculated Air Option

Control Settings

System Response

Fan Switch

Mode Switch

A/C Push Button

A/C Signal

A/C Indicator

Comments

ON

U, B, L

OFF

LOW

OFF

The A/C signal and the A/C indicator are on according to the position of the push button when the mode switch is in any of the following positions:

    • Upper
    • Bi-Level
    • Lower

ON

U, B, L

OFF

LOW

OFF

ON

U, B, L

ON

HIGH

ON

ON

U, B, L

ON

HIGH

ON

ON

M, BL, DF

OFF (3)

HIGH (1)

OFF

When in Max (Pontiac Only), Blend or Defrost mode, the following conditions occur:

    • The A/C signal defaults to high
    • The indicator lights according to the position of the push button.

ON

M, BL, DF

OFF (3)

HIGH (1)

OFF

ON

M, BL, DF

ON (3)

HIGH

ON

ON

M, BL, DF

ON (3)

HIGH

ON

OFF

U, B, L

(2)

LOW (1)

OFF

When the fan switch is off, the following conditions occur:

    • The A/C signal defaults to low
    • The indicator is off

OFF

U, B, L

(2)

LOW (1)

OFF

OFF

BL, DF

(2)

LOW (1)

OFF

1. Default Condition 2. Not Allowed 3. Previous Switch State

M-Max (Pontiac Only) U-Upper B-Bi-Level L-Lower BL-Blend DF-Defrost

Outside Recirculated Air Option (Oldsmobile Only)

Control Settings

System Response

Fan Switch

Mode Switch

A/C Push Button

OSA/REC Push Button

Recirculation Vacuum

Recirculation Indicator

OSA Indicator

Comments

ON

U, B, L

OFF

OSA

OFF

OFF

ON

The vacuum and the indicators are on according to the position of the push buttons when the mode switch is in any of the following positions:

    • Upper
    • Bi-Level
    • Lower

ON

U, B, L

OFF

RECIRC

ON

ON

OFF

ON

U, B, L

ON

OSA

OFF

OFF

ON

ON

U, B, L

ON

RECIRC

ON

ON

OFF

ON

BL, DF

OFF (3)

OSA

OFF

OFF

ON

The vacuum defaults to off and the OSA indicator is lit when the mode switch is in the following settings:

    • Blend
    • Defrost

ON

BL, DF

OFF (3)

RECIRC (2)

OFF (1)

OFF

ON

ON

BL, DF

ON (3)

OSA

OFF

OFF

ON

ON

BL, DF

ON (3)

RECIRC (2)

OFF (1)

OFF

ON

OFF

U, B, L

(2)

OSA

OFF

OFF

ON

When the fan switch is off, the vacuum and the indicators follow the settings according to the position of the push buttons.

OFF

U, B, L

(2)

RECIRC

ON

ON

OFF

OFF

BL, DF

(2)

(2)

OFF (1)

OFF

ON

1. Default Condition 2. Not Allowed 3. Previous Switch State

U-Upper B-Bi-Level L-Lower BL-Blend DF-Defrost