GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 LSS 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Functional Check

Functional Check Buick

Set A/C Controls

Result

The following procedures test the manual air conditioning system. You may complete all of the steps in each procedure without using any tools. Complete this procedure under the following conditions:

    • The temperature outside of the vehicle is 16°C (60°F) or higher.
    • The engine is running.

In order to effectively diagnose a manual air conditioning system condition, use the diagnostic procedure outlined in this section. Perform each step in the order presented.

Engine running

Set A/C control to OFF
  • The OFF LED illuminates.

Press NORM

Temperature Selector: COOL

Blower Control: HIGH
    • The NORM LED illuminates.
    • Cool air flows from the instrument panel outlets.
    • The blower runs at high speed. The compressor turns ON.

Press MAX
    • The MAX LED illuminates.
    • Cool air flows from the instrument panel outlets.
    • Blower noise changes.
    • The compressor continues to operate.

Press BI-LEV
    • The BI-LEV LED illuminates.
    • Cool air flows from the panel outlets and from the floor outlets.
    • The compressor continues to operate.

Press RECIRC
    • The RECIRC LED illuminates.
    • Cool air flows from the instrument panel outlets.

Press FRONT

Temperature Selector: WARM
    • The FRONT LED illuminates.
    • Warm air flows from the defroster outlets.
    • The compressor continues to operate.

Press VENT
    • The VENT LED illuminates.
    • The compressor turns OFF.
    • Warm air flows from the instrument panel outlets.

Press HRT
    • The HRT LED illuminates.
    • Warm air flows from the floor outlets.

Press BLEND
    • The BLEND LED illuminates.
    • Warm air flows from the defroster outlets and from the floor outlets.

Press OFF
  • The blower turns OFF.

Press HRT
  • The blower returns to high speed.

Blower Control: Move from HIGH to LOW
  • The blower speed reduces each time you move the switch.

Functional Check Oldsmobile

Set A/C Controls

Result

The following procedures test the manual air conditioning system. You may complete all of the steps in each procedure without using any tools. Complete this procedure under the following conditions:

    • With the temperature outside of the vehicle at 16°C (60°F) or higher
    • With the engine running

In order to effectively diagnose a manual air conditioning system condition, use the diagnostic procedure outlined in this section. Perform each step in the order presented.

Mode Selector: OFF

Fan: LO
  • Blower is not running.

Mode Selector: LOWER

Temperature Selector: FULL WARM
    • The blower runs at low speed.
    • Warm air flows from the floor outlets.

Increase the Blower Speed from LO to HI
  • Increased air flow at each step.

Mode Selector: DEF
    • Air flows from the defroster outlets.
    • The compressor turns ON.
    • The air becomes warm.

Mode Selector: UPPER
    • Outside air flows from the A/C instrument panel.
    • The compressor is off.

Mode Selector: BI-LEV

Temperature Selector: FULL COLD
    • Cold air flows from the center instrument panel outlet and from the floor outlets.
    • The compressor turns ON.

Mode Selector: RECIRC
    • Blower noise will increase when the outside air valve closes.
    • The compressor continues to operate.

Mode Selector: DEFOG
    • Air flows from the defroster outlets and from the floor outlets.
    • The compressor continues to operate.

Mode Selector: OFF
    • The blower turns OFF.
    • The compressor turns OFF.

Functional Check Pontiac

Set A/C Controls

Result

The following procedures test the manual air conditioning system. You may complete all of the steps in each procedure without using any tools. Complete this procedure under the following conditions:

    • With the temperature outside of the vehicle at 16°C (60°F) or higher
    • With the engine running

In order to effectively diagnose a manual air conditioning system condition, use the diagnostic procedure outlined in this section. Perform each step in the order presented.

Mode Selector: OFF

Fan: LO
  • The blower is not running.

Mode Selector: HEAT

Temperature Selector: FULL WARM
    • The blower runs at low speed.
    • Warm air flows from the floor outlets.

Increase the Blower Speed from LO to HI
  • Increased air flow at each step.

Mode Selector: DEF
    • Air flows from the defroster outlets.
    • The compressor turns ON.
    • Air becomes warm.

Mode Selector: VENT
    • Outside air flows from the A/C instrument panel.
    • The compressor is OFF.

Mode Selector: BI-LEV

Temperature Selector: FULL COLD
    • Cold air flows from the center instrument panel outlets and from the floor outlets.
    • The compressor turns ON.

Mode Selector: A/C
    • Cold air flows from the center instrument panel outlets.
    • The compressor turns ON.

Mode Selector: MAX
    • Blower noise will increase when the air inlet valve closes.
    • The compressor continues to run.
    • Air flows from the instrument panel outlets.

Mode Selector: DEFOG
    • Air flows from the defroster outlet and from the floor outlets.
    • The compressor continues to run.

Mode Selector: OFF
    • The blower turns OFF.
    • The compressor turns OFF.