B1058-11

B1058-11-RECIRCULATION DOOR CONTROL - CIRCUIT SHORT TO GROUND







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 Diagnostic Trouble Codes (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.

- Set Condition:
The A/C Heater Control detects a short to ground on the Recirculation Door Driver circuit. If the A/C Heater Control detects valid current draw, 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. HVAC Pre-Diagnostic Troubleshooting Procedure.

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 6

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




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. 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 the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 4

4. 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 the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 5

5. 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 the HVAC VERIFICATION TEST. HVAC Verification Test.

No

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

6. 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 wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
4. 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.