Air Recirculation Malfunction

Air Recirculation Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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/System Description

The recirculation actuator is a 3-wire bi-directional electric motor. Ignition 3 voltage, ground and control circuits enable the actuator to operate. The control circuit uses a 0-12 volts linear-ramped signal to command the actuator movement. The 0 and 12-volt control values represent the opposite limits of the actuator range of motion. The values in between 0 and 12 volts correspond to the positions between the limits.

When the HVAC control assembly sets a commanded, or targeted, value, the control signal is set to a value between 0-12 volts. The actuator shaft rotates until the commanded position is reached. The module will maintain the control value until a new commanded value is needed.

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.

Circuit/System Verification

1. Ignition ON, engine running, place the blower motor switch at the maximum speed position and the mode switch in the vent or panel position.
2. Press the recirculation control switch from the recirc position to the outside air position. The recirculation actuator should follow the commanded states of recirc to outside air.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the recirculation actuator.
2. Test for less than 1.0 ohm between the recirculation actuator ground circuit terminal 7 and ground.

^ If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the recirculation actuator ignition circuit terminal 5 and ground.

^ If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, replace the recirculation actuator.

4. Install a DMM between the control circuit terminal 6 and ground. Command the actuator in each direction. Voltage on the control circuit should change from 0 volts when commanding the actuator in one direction to 12 volts in the other direction.

^ If the voltage does not change as specified, replace the HVAC control module.

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Recirculation Door Replacement