Circuit Description
The auxiliary mode actuator is an electronic device that incorporates a stepper motor and feedback potentiometer. The auxiliary HVAC control module control assemblies; control the auxiliary mode door position by sending a control signal to the actuator. The signal's value is dependent upon the desired mode selected by the vehicle occupants. As the actuator moves, the potentiometer produces the actual door position signal that is sent to the rear auxiliary HVAC control module. The rear auxiliary HVAC control module continues to command the actuator to move until the desired and actual values are equal. The door directs airflow through the outlets as selected by the vehicles occupants.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | Ignition voltage is between 9-16 volts. |
| • | An auxiliary mode actuator positional change is attempted. |
Conditions for Setting the DTC
The actual auxiliary mode door position differs from the commanded mode door position by 4 counts or more.
Action Taken When the DTC Sets
The auxiliary mode actuator is considered stalled and the HVAC control module will command the auxiliary mode actuator to stop rotation (2.5 V).
Conditions for Clearing the DTC
| • | If the rear auxiliary HVAC control module no longer detects a failure, then the DTC will become history. |
| • | The history DTC will clear after 50 ignition cycles without a failure. |
| • | The DTC can be cleared with a scan tool. |
Diagnostic Aids
| • | A dead zone exists in a range 10 counts above or below the mode door max or mode door min positions. When the mode door actual data parameter is within the dead zone, the DTC will not set. If the mode door commanded data parameter differs from the mode door actual data parameter by 4 counts or more outside the dead zone, the DTC will set. |
| • | A damaged or broken auxiliary mode door and or actuator can cause this DTC to set. |
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: HVAC Air Delivery/Temperature Control Schematics | ||||||||||
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check | ||||||
2 |
Does the scan tool indicate that the auxiliary mode actuator Commanded data parameter is within the specified value of the auxiliary mode actuator Actual data parameter? | 0-3 counts | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | ||||||
3 |
Does the scan tool indicate that the auxiliary mode actuator actual parameter changes within the specified range when it is commanded from floor to upper outlets? | 5-250 counts | Go to diagnostic aids | Go to Step 4 | ||||||
4 | Test the mode door ignition 3 circuit of the auxiliary mode actuator for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 5 | ||||||
5 | Test the 5 volt reference circuit of the mode actuator for an open. high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 6 | ||||||
6 | Test the mode door control - auxiliary circuit for an open, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 7 | ||||||
7 | Test the 5 volt reference circuit of front auxiliary HVAC control module for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 8 | ||||||
8 |
Important: The air temperature actuator connector and the HVAC control module connector must be connected to correctly perform test.
Does the drive shaft of the auxiliary mode actuator rotate and do the counts change? | -- | Go to Step 11 | Go to Step 9 | ||||||
9 | Inspect the auxiliary mode actuator door and the auxiliary mode actuator for the following:
Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 | ||||||
10 | Inspect for poor connections at the harness connector of the auxiliary mode actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 12 | ||||||
11 | Inspect for poor connections at the harness connector of the rear auxiliary HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 | ||||||
12 | Replace the auxiliary mode actuator. Refer to Auxiliary Blower Motor Replacement in Heating Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 14 | -- | ||||||
13 |
Important: Perform the recalibration procedure for the HVAC control module. Replace the rear auxiliary HVAC control module. Refer to Control Assembly Replacement - Auxiliary . Did you complete the replacement? | -- | Go to Step 14 | -- | ||||||
14 |
Does the DTC reset? | -- | Go to Step 2 | SYSTEM OK | ||||||
