Air Delivery Improper - Auxiliary
Air Delivery Improper - Auxiliary
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 auxiliary mode 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 auxiliary mode door and the auxiliary mode actuator for the following conditions:
* A misaligned auxiliary mode actuator.
* Broken or binding linkages or auxiliary mode door.
* An obstruction that prevents the auxiliary mode door from operating within its full range of motion.
* Missing seals to the auxiliary mode door.
* Misaligned seals to the auxiliary mode door.
Circuit/System Verification
1. Ignition ON, engine running, place the auxiliary blower motor switch at the maximum speed position.
^ If the auxiliary blower motor is inoperative, refer to Auxiliary Blower Motor Malfunction (RPO C36) Auxiliary Blower Motor Malfunction (RPO C69 w/o Rear Controls) Auxiliary Blower Motor Malfunction (RPO C69 with Rear Controls). Auxiliary Blower Motor Malfunction (RPO C36) Auxiliary Blower Motor Malfunction (RPO C69 w/o Rear Controls) Auxiliary Blower Motor Malfunction (RPO C69 with Rear Controls)
2. Rotate the auxiliary mode control switch from the VENT position to the FLOOR position. The air flow should follow the commanded states and blow through the vent outlets and then floor outlets.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the auxiliary mode actuator.
2. Test for less than 1.0 ohm between the auxiliary mode 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 auxiliary mode actuator ignition circuit terminal 10 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 auxiliary mode actuator.
4. Install a DMM between the control circuit terminal 8 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 auxiliary HVAC control module.
5. If all circuits test normal, test or replace the auxiliary mode actuator.
Component Testing
1. Install a 10-amp fused jumper wire between the control terminal 8 and 12 volts. Momentarily install a jumper wire between the control terminal 7 and ground. The auxiliary mode actuator shaft should rotate.
^ If the function does not perform as specified, replace the auxiliary mode actuator.
2. Install a 10-amp fused jumper wire between the control terminal 10 and 12 volts. Momentarily install a jumper wire between the control terminal 7 and ground. The auxiliary mode actuator shaft should rotate.
^ If the function does not perform as specified, replace the auxiliary mode actuator.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Mode Valve Actuator Replacement - Auxiliary.
* Refer to Programming and Relearning. Programming and Relearning