For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Circuit/System Description

The air temperature door is a mechanical cable operated door.

### Reference Information

#### Schematic Reference

HVAC Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

• | Air Temperature Description and Operation

• | Air Delivery Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Start the engine, place the mode switch in the Vent position. Place the blower motor in the high speed position and the air temperature to the coldest setting. The A/C compressor clutch should engage.

⇒ | If the HVAC compressor clutch does not engage , refer to the Air Conditioning Compressor Malfunction .

2. Ignition ON, place the blower switch in each speed position, the blower motor should operate in each speed.

⇒ | If the blower motor does not function properly in each speed position, refer to Blower Motor Malfunction .

3. Place the recirculation switch in each position. The recirculation door should move from the outside air position to the recirculate position.

⇒ | If the recirculation door does not function properly in each position, refer to Air Recirculation Malfunction .

4. Inspect the air temperature door for the following conditions:

• | High effort to operate the air temperature door

• | Broken or binding linkages

• | An obstruction that prevents the air temperature door from moving it's full range

• | Missing seals to the air temperature doors

• | Misaligned seals to the air temperature door

⇒ | If any of the above conditions exist, refer to the appropriate corrective action.