GM Service Manual Online
For 1990-2009 cars only

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 Circuit A

1

1

1

Recirculation Door Control Circuit B

1

1

1

1. Recirculation Actuator Inoperative Horn 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.

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. 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 in one direction to the other direction.
  3. If the test lamp is always OFF, test the appropriate control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
    If the test lamp is always ON, test the appropriate control circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.
  4. If all circuits test normal, test or replace the recirculation actuator.

Circuit/System Testing

  1. Install a 10-amp 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.
  2. If the function does not perform as specified, replace the recirculation actuator.
  3. Reverse the jumper wires, the recirculation actuator shaft should rotate.
  4. 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