Floor/Defrost Mode Door Control Circuit Open

B1049-FLOOR/DEFROST MODE DOOR CONTROL CIRCUIT OPEN





For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.

Theory of Operation

After the initial installation of the Front A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The Front A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar DTCs can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present.

- When Monitored:
With the ignition on and a HVAC Actuator Calibration Test is performed.

- Set Condition:
If less than five feedback pulses are detected in both clockwise and counterclockwise directions during a HVAC Actuator Calibration Test. If a HVAC Actuator Calibration Test is performed and the Heater A/C Control detects a valid door movement in both directions, the DTC will change from Active to Stored and will stay in the controllers memory for 100 ignition cycles.





Always perform the HVAC Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview.

1. PERFORM HVAC CALIBRATION ACTUATOR TEST
1. Ignition on, engine not running.
2. With the scan tool, erase HVAC DTCs and perform the HVAC Actuator Calibration Test.

Did this DTC reset?

Yes

- Go To 2

No

- Go To 5

2. CHECK THE (C801) MODE DOOR 2 DRIVER CIRCUIT FOR AN OPEN




1. Turn the ignition off to the lock position.
2. Disconnect the Front Mode Door (Floor/Defrost) Actuator harness connector.
3. Measure the resistance of the (C801) Mode Door 2 Driver circuit between the A/C Heater Control C1 harness connector and the Front Mode Door (Floor/Defrost) harness connector.

Is the resistance above 5.0 Ohms?

Yes

- Repair the (C801) Mode Door 2 Driver circuit for an open.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 3

3. CHECK THE (C34) COMMON DOOR DRIVER 1 CIRCUIT FOR AN OPEN




1. Measure the resistance of the (C34) Common Door Driver 1 circuit between the A/C Heater Control C1 harness connector and the Front Mode Door (Floor/Defrost) Actuator harness connector.

Is the resistance above 5.0 Ohms?

Yes

- Repair the (C34) Common Door Driver 1 circuit for an open.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 4

4. CHECK THE FRONT MODE DOOR (FLOOR/DEFROST) ACTUATOR AND THE FRONT A/C HEATER MODULE
1. Replace the Front Mode Door (Floor/Defrost) Actuator.
2. With the scan tool, erase HVAC DTCs and perform the HVAC Actuator Calibration Test.

Did this DTC reset?

Yes

- Replace and program the Front A/C Heater Module.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Test complete.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

5. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. With the scan tool, check the Environmental Data to help identify the conditions in which the DTC was set.
3. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
4. Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, partially broken wires.
5. Check the connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals.
6. Wiggle the wiring and connectors while checking for shorted and open circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Test complete.