Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Mode Door Control Circuit A | 1 | 1 | 1 | -- |
Mode Door Control Circuit B | 1 | 1 | 1 | -- |
1. Mode Actuator Inoperative | ||||
Circuit Description
| • | B0248 Mode actuator |
| • | B0268 Recirculation actuator |
| • | B0418 Right Air temperature actuator |
| • | B0408 Left Air temperature actuator |
The mode 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 mode door and the mode actuator for the following conditions:
| • | A misaligned mode actuator. |
| • | Broken or binding linkages or mode door. |
| • | An obstruction that prevents the mode door from operating within its full range of motion. |
| • | Missing seals to the mode door. |
| • | Misaligned seals to the mode door. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Conditions for Running the DTC
The HVAC control module has completed a calibration/recalibration of the actuator.
Conditions for Setting the DTC
The HVAC control module does not detect any movement of the actuator after two unsuccessful attempts at moving the actuator.
Action Taken When the DTC Sets
The HVAC control module will recalibrate the appropriate actuator each time the ignition switch is turned ON.
Conditions for Clearing the DTC
| • | The DTC will become history if the HVAC control module no longer detects a failure. |
| • | The history DTC will clear after 100 fault free ignition cycles. |
| • | The DTC can be cleared with a scan tool. |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the mode actuator.
- 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.
- If all circuits test normal, test or replace the mode actuator.
| ⇒ | 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. |
Component Testing
- 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 mode actuator shaft should rotate.
- Reverse the jumper wires; the mode actuator shaft should rotate.
| ⇒ | If the function does not perform as specified, replace the mode actuator. |
| ⇒ | If the function does not perform as specified, replace the mode actuator. |
Repair Instructions
Perform the after completing the diagnostic procedure.
