Important: Conduct the Function Test of the heater system with the vehicle at idle. Before beginning the test, allow the vehicle to idle until the coolant is hot and the thermostat is open. The coolant temperature should be 90°C (194°F). If you find a problem during any intermediate step of the Function Test, complete the test before beginning any needed repairs.

OFF

COLD (BLUE)

LOW-HIGH

OFF

No Air Flow

No Air Flow

No Air Flow

1,3

VENT

COLD

HIGH

HIGH

No Air Flow

Air Flow

No Air Flow

1,2,3,4,6

BLEND (HEATER/ VENT)

COLD

HIGH

HIGH

Air Flow

Air Flow

No Air Flow

1,2,3,5,6

HEATER

HOT (RED)

HIGH

HIGH

Air Flow

No Air Flow

Minimum Air Flow

1,2,3,6

BLEND (HEATER/ DEFROST)

HOT

HIGH

HIGH

Air Flow

No Air Flow

Air Flow

1,2,3,6

DEFROST

HOT

HIGH

HIGH

Minimum Air Flow

No Air Flow

Air Flow

1,2,3,6

Remarks

1. The speed of the blower must increase as the fan switch moves from the LOW position to the HIGH position.
2. Feel the engagement of the detent in each mode.
3. Check for airflow at the side window defogger outlets.
4. Air temperature from the ducts should be nearly the same temperature as the outside air.
5. All air should be hot.
6. Move the temperature knob from the full HOT (red) position to the full COLD (blue) position. Ensure that the air temperature drops back to nearly the temperature of the outside air.