Floor/Defrost Mode Door Control Circuit/Performance

B1046-FLOOR/DEFROST MODE DOOR CONTROL CIRCUIT/PERFORMANCE





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:
Continuously with the ignition on and whenever the door actuator is commanded to move.

- Set Condition:
If an actuator move is commanded by the Front A/C Heater Module and an overcurrent condition is detected in either clockwise or counterclockwise movement for the period of five seconds. If the Front A/C Heater Module detects valid current draw for 10 seconds, 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 ACTUATOR DTC DETECTION TEST
1. Ignition on, engine not running.
2. With the scan tool, perform the HVAC Actuator DTC Detection Test.

Did any control circuit low or high DTCs set?

Yes

- Testing and Inspection Perform the appropriate diagnostic procedure.

No

- Go To 2

2. CHECK IF DTC IS ACTIVE
1. With the scan tool, read HVAC DTCs.

Is this DTC active?

Yes

- Go To 3

No

- Go To 7

3. CHECK THE (C801) MODE DOOR 2 DRIVER CIRCUIT FOR A SHORT TO VOLTAGE




1. Turn the ignition off to the lock position.
2. Disconnect the A/C Heater Control C1 harness connector.
3. Disconnect the Front Mode Door (Floor/Defrost) Actuator harness connector.
4. Ignition on, engine not running.
5. Measure the voltage of the (C801) Mode Door 2 Driver circuit.

Is there any voltage present?

Yes

- Repair the (C801) Mode Door 2 Driver circuit for a short to voltage.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 4

4. CHECK THE (C801) MODE DOOR 2 DRIVER CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off to the lock position.
2. Measure the resistance between ground and the (C801) Mode Door 2 Driver circuit.

Is the resistance below 100k Ohms?

Yes

- Repair the (C801) Mode Door 2 Driver circuit for a short to ground.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 5

5. CHECK THE FRONT MODE DOOR (FLOOR/DEFROST)
1. Remove the Front Mode Door (Floor/Defrost) Actuator and check the Front Mode Door (Floor/Defrost) for binding and full travel.

Were there any problems found?

Yes

- Repair or replace the Front Mode Door (Floor/Defrost) as necessary.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 6

6. 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 DTC Detection 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.

7. 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.