HVAC, ATC

B1058-RECIRCULATION DOOR CONTROL CIRCUIT/PERFORMANCE





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

Theory of Operation

After the initial installation of the A/C Heater Control, 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 A/C Heater Control 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 an actuator movement is commanded by the A/C Heater Control.

- Set Condition:
If an actuator move is commanded by the A/C Heater Control and there are no feedback pulses detected in that direction, the controller commands the actuator in the opposite direction. If feedback pulses are detected in only one direction this DTC will set. If the A/C Heater Control detects a valid pulse feedback 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. CHECK IF DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, read HVAC DTCs.

Is this DTC active?

Yes

- Go To 3

No

- Go To 2

2. PERFORM HVAC ACTUATOR CALIBRATION TEST
1. With the scan tool, perform the HVAC Actuator Calibration Test.

Did this DTC change from Stored to Active while performing the HVAC Actuator Calibration Test?

Yes

- Go To 3

No

- Go To 9

3. CHECK THE (C32) RECIRCULATION DOOR 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 Recirculation Door Actuator harness connector.
4. Ignition on, engine not running.
5. Measure the voltage of the (C32) Recirculation Door Driver circuit.

Is there any voltage present?

Yes

- Repair the (C32) Recirculation Door Driver circuit for a short to voltage.
- Perform HVAC VERIFICATION TEST HVAC Verification Test.

No

- Go To 4

4. CHECK THE (C34) COMMON DOOR DRIVER CIRCUIT FOR A SHORT TO VOLTAGE




1. Measure the voltage of the (C34) Common Door Driver circuit.

Is there any voltage present?

Yes

- Repair the (C34) Common Door Driver circuit for a short to voltage.
- Perform HVAC VERIFICATION TEST HVAC Verification Test.

No

- Go To 5

5. CHECK THE (C32) RECIRCULATION DOOR DRIVER CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off to the lock position.
2. Measure the resistance between ground and the (C32) Recirculation Door Driver circuit.

Is the resistance below 100k Ohms?

Yes

- Repair the (C32) Recirculation Door Driver circuit for a short to ground.
- Perform HVAC VERIFICATION TEST HVAC Verification Test.

No

- Go To 6

6. CHECK THE (C34) COMMON DOOR DRIVER CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (C34) Common Door Driver circuit.

Is the resistance below 100k Ohms?

Yes

- Repair the (C34) Common Door Driver circuit for a short to ground.
- Perform HVAC VERIFICATION TEST HVAC Verification Test.

No

- Go To 7

7. CHECK THE RECIRCULATION DOOR
1. Remove the Recirculation Door Actuator and check the Recirculation Door for binding and full travel.

Were there any problems with the Recirculation Door movement?

Yes

- Repair or replace the Recirculation Door as necessary.
- Perform HVAC VERIFICATION TEST HVAC Verification Test.

No

- Go To 8

8. CHECK THE RECIRCULATION DOOR ACTUATOR
1. Replace the Recirculation Door 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 A/C Heater Control.
- Perform HVAC VERIFICATION TEST HVAC Verification Test.

No

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

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

Were there any problems found?

Yes

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

No

- Test complete.