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.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Recirculation Door Control A | 1 | 1 | 1 | --
Recirculation Door Control B | 1 | 1 | 1 | --
1. Recirculation Actuator Inoperative

### Circuit/System Description

The recirculation actuator is a 2-wire bi-directional electric motor. There are 2 control circuits that enable the actuator to operate. The control circuits use either a 0 or 12-volt value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 volts. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 volts. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction.

### Diagnostic Aids

Inspect the recirculation door and the recirculation actuator for the following conditions:

• | A misaligned recirculation actuator

• | Broken or binding linkages or recirculation door

• | An obstruction that prevents the recirculation door from operating within its full range of motion

• | Missing seals to the recirculation door

• | Misaligned seals to the recirculation 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

Ignition ON, observe the operation of the drive shaft of the recirculation actuator while using the recirculation control switch. The drive shaft of the recirculation actuator should rotate.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the recirculation actuator.
2. Ignition ON, connect a test lamp between the control circuit terminal A and control circuit terminal B. Command the actuator in each direction. The test lamp should briefly illuminate when commanding the actuator from one direction to the other.

⇒ | If the test lamp is always OFF, test both control circuits for a short to ground or an open/high resistance. If the circuits test normal, replace the HVAC control module.

⇒ | If the test lamp is always ON, test both control circuits for a short to voltage. If the circuits test normal, replace the HVAC control module.

3. If all circuits test normal, test or replace the recirculation actuator.

### Component Testing

1. Install a 10A fused jumper wire between the control terminal A and 12 volts. Momentarily install a jumper wire between the control terminal B and ground. The recirculation actuator shaft should rotate.

⇒ | If the function does not perform as specified, replace the recirculation actuator.

2. Reverse the jumper wires; the recirculation actuator shaft should rotate.

⇒ | If the function does not perform as specified, replace the recirculation actuator.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Recirculation Actuator Replacement

• | Control Module References for HVAC replacement, setup, and programming