GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1998 🢒 Riviera 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 Functional Check

Functional Check Oldsmobile

Action

Normal Result

    • Warm the engine. Run the engine at IDLE.
    • Ensure that the outside temperature is at least 5°C (41°F).
    • If the engine was recently running, you may encounter a purge delay of approximately 20 seconds before the air conditioning unit activates the selected mode. This delay is normal. This delay is designed in order to prevent windshield fogging.
    • In order to prevent windshield frosting during a cold start up with cold outside temperatures, the system delays the start of all operation modes (except DEFROST mode) until the engine is warm.

Rotate the MODE knob to the OFF position.
    • The outside temperature is displayed.
    • The blower is set to the OFF position.
    • The OFF LED will turn ON.
    • Rotate the MODE knob to the upper icon.
    • Select either the HIGH or the LOW fan settings by rotating the FAN knob.
    • The upper icon LED will turn ON.
    • The air delivery indicator is displayed and the SET TEMP LED is displayed.
    • The blower operates, and the corresponding number of fan segment bars display.
    • Air flows from the A/C IP outlets, and the outside temperature is displayed after 5 seconds.
    • If the outside temperature is above 5°C (41°F), the compressor turns ON.

Press the MODE knob once and push the TEMP button in order to decrease the set temperature.
    • The temperature display drops one degree at a time to 18°C (65°F). Then the display jumps to 16°C (60°F).
    • Cool air flows from the A/C IP outlets.
    • The blower speed increases to maximum force.
    • If the outside temperature is above 5°C (41°F), the compressor turns ON.
    • Select the heater and A/C system settings:
       - Use the steering wheel controls.
       - Use the control assembly.
    • The outside temperature displays after 5 seconds.

Push the TEMP button in order to increase the set temperature.
    • The temperature display increases one degree at a time to 29°C (85°F). Then the display jumps to 32°C (90°F).
    • The air flow becomes warm.
    • The blower operates at maximum speed (the speed will vary while the temperature display is changing).
    • If the outside temperature is above 5°C (41°F), the compressor turns ON.
    • The outside temperature displays after 5 seconds.

Rotate the MODE knob to the upper and to the lower (blend) icon.
    • The BLEND LED will turn on.
    • Air flows from the IP and the floor outlets.
    • The SET TEMP LED will display for 5 seconds.
    • If the outside temperature is above 5°C (41°F), the compressor turns ON.
    • The outside temperature displays after 5 seconds.

Rotate the MODE knob to the lower icon.
    • The LOWER LED will turn on.
    • The SET TEMP LED will display for 5 seconds.
    • Air is directed to the heater outlets.

Rotate the MODE knob to the defog/floor icon.
    • The air flows from the windshield and the floor outlets.
    • If the outside temperature is above 5°C (41°F), the compressor turns ON.
    • The outside temperature displays after 5 seconds.

Rotate the MODE knob to DEF (defrost).
    • The DEFOG LED will turn on.
    • The air flows from the windshield and the floor outlets.
    • If the outside temperature is above 6°C (43°F), the compressor turns ON.
    • The outside temperature displays after 5 seconds.
    • Select AUTO.
    • Press the A/C button.
    • The A/C button LED will turn off.
    • The compressor cycles off.
    • Select AUTO.
    • Press the A/C button.
    • The A/C ON LED will turn on.
    • The compressor is on.
    • Sensor inputs determine air delivery.
    • Set the temperature to 24°C (75°F).
    • Close all of the doors and the windows on the vehicle.
    • Press the MODE knob.
    • The temperature display advances to 24°C (75°F) and the system adjusts its in-vehicle temperature toward 24°C (75°F).
    • The outside temperature displays after 5 seconds.
    • The blower speed reduces to minimum as the in-vehicle temperature nears 24°C (75°F).

Set the fan to LOW speed.
    • The blower speed reduces until only one fan bar is lit.
    • One LED is lit.
        

Set the fan to HIGH speed. If the vehicle is equipped with steering wheel controls, repeat the test using the FAN button on the steering wheel.
    • The blower speed increases until all of the fan bars are lit.
    • All of the LEDs are lit.
    • Turn the ignition switch to the OFF position.
    • Wait for several seconds.
    • Return the switch to the RUN position.
    • The outside temperature displays after 5 seconds.
    • The heater and A/C control assembly returns to the same setting as before the ignition was turned off.
    • Set the temperature to 18°C (65°F).
    • Set the passenger climate control to full warm.

The temperature on the passenger side of the vehicle is noticeably warmer than the temperature on the driver side.

    • Set the temperature to 29°C (85°F).
    • Set the passenger climate control to full cold.

The temperature on the passenger side of the vehicle is noticeably cooler than the temperature on the driver side.

Functional Check Buick

Action

Normal Result

    • Warm the engine. Run the engine at IDLE.
    • Ensure that the outside temperature is at least 5°C (41°F).
    • If the engine was recently running, you may encounter a purge delay of approximately 20 seconds before the air conditioning unit activates the selected mode. This delay is normal. This delay is designed in order to prevent windshield fogging.
    • In order to prevent windshield frosting during a cold start up with cold outside temperatures, the system delays the start of all operation modes (except DEFROST mode) until the engine is warm.

Press the FRONT button.
    • The FRONT LED will turn on.
    • The WINDSHIELD LED will turn on and the air distribution indicator arrow appears.
    • The SET TEMP LED is displayed.
    • Air flows from the defroster outlets.
    • After 10 seconds, the SET TEMP display switches to the outside air temperature.

Press the AIR FLOW button.

The control head displays the system status for 10 seconds, then the display returns to EXT .

While pressing the bottom of the AIR FLOW button, set the air distribution to FLOOR and WINDSHIELD.
    • The WINDSHIELD LED and the FLOOR LED will turn on and the air distribution indicator arrows appear.
    • The SET TEMP LED is displayed.
    • Air flows from the windshield defroster and heater outlets.
    • After 10 seconds, the SET TEMP display changes to EXT. The rest of the display remains the same.

While pressing the top of the AIR FLOW button, set the air distribution to MID.
    • The MID LED will turn on and the air distribution indicator arrows (up and down) appear.
    • The SET TEMP LED is displayed.
    • Air flows from the IP outlets.
    • After 10 seconds, the SET TEMP display changes to EXT. The rest of the display remains the same.

Using the AIR FLOW button, set the air distribution to FLOOR and MID.
    • The MID LED will turn on and the air distribution indicator up arrow appears. The FLOOR LED will turn on and the air distribution indicator arrow appears.
    • The SET TEMP LED is displayed.
    • Air flows from the IP and the heater outlets.
    • After 10 seconds, the SET TEMP display changes to EXT. The rest of the display remains the same.

Using the AIR FLOW button, set the air distribution to FLOOR.
    • The FLOOR LED will turn on and the air distribution indicator arrow appears.
    • The SET TEMP LED is displayed.
    • Air flows from the heater outlets.
    • After 10 seconds, the SET TEMP display changes to EXT. The rest of the display remains the same.

Press the FAN button, holding the button up. Then hold the button down.
    • The fan icon is displayed and the fan segment bars are displayed.
    • The fan speed and the air power rise and fall with the fan speed selection.
    • The number of fan segment bars rises and falls with the fan speed selection.

Press the TEMP button, holding the button up. Then hold the button down.
    • The SET TEMP LED is displayed.
    • The SET TEMP display scrolls 1° at a time up and down, jumping from 29°C (85°F) to 32°C (90°F) and from 15°C (60°F) to 18°C (65°F).
    • The outlet air temperature slowly rises and falls with the SET TEMP display.
    • Press the AUTO button.
    • Then press the TEMP button and slowly lower the temperature to 18°C (65°F).
    • The AUTO LED turns on.
    • The outlet air temperature slowly changes.
    •  The air flow switches from the heater to the IP outlets. (You will notice a brief interval when the air flows from the defroster and the heater outlets during this transition.)
    • The fan speed changes from HIGH to LOW and back to HIGH.
    • After 10 seconds, the SET TEMP display changes to EXT. The rest of the display remains the same.

Press the recirculation (RECIRC) button.
    • The RECIRC LED turns on.
    • The air noise from the blower motor changes as the system goes from outside air to recirculated air.

Press the VENT button.
    • The VENT LED turns on.
    • The RECIRC LED turns off.
    • The recirculation door closes.
    • The A/C compressor turns off.
    • You cannot run the VENT and RECIRC modes simultaneously.

Press the REAR button.
    • The REAR LED turns on.
    • The defogger grid warms.
    • The REAR LED turns off automatically when the defogger times out or when you press the REAR button again.
    • Set the AIR FLOW to MID.
    • Set the PASSENGER CONTROL dial.
    • The orange center LED bar displays and the words WARMER and COOLER display.
    • The orange LED does not indicate AIR TEMPERATURE OFF.
    • Adjust the PASSENGER CONTROL dial to WARM,
    • Set the dial to COOL.
    • The segment bars rise and fall with the WARM and COOL buttons.
    • The AIR TEMPERATURE OFF indicator slowly rises and falls with the WARM and COOL selections.