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Blend Calibration Fault (Dual-Zone)

BLEND CALIBRATION FAULT (DUAL-ZONE)

Blend Calibration Fault (Dual-Zone):





Theory of Operation

NOTE: Diagnose and repair Actuator Circuit Test faults before diagnosing Overcurrent faults and Calibration faults. Diagnose and repair Overcurrent faults before diagnosing Calibration faults.

The purpose of actuator calibration is to determine the total span of door travel between physical stops. To calibrate the actuator, the A/C Heater Control first moves the door to its soft stop, and then counts the number of pulses it takes to move the door to its other stop. An expected range of span is stored in the control's memory. If the measured calibration value is not within the expected range, this fault will set.

For vehicles equipped with electric backlight (EBL), running the HVAC Door Recalibration will cause the EBL status indicator to flash. If recalibration fails, the EBL status indicator will continue to flash until either the system passes recalibration or the ignition key is cycled. When the EBL status indicator is flashing, it will not indicate EBL operating status. However, the EBL mode switch will continue to function normally. When the EBL status indicator is flashing, the A/C status indicator will not function. However, the A/C mode switch will continue to function normally.

For vehicles not equipped with electric backlight (EBL), no status indicator will flash when running the HVAC Door Recalibration. If recalibration fails, the A/C status indicator will not function, however, the A/C mode switch will continue to function normally.

WHEN MONITORED
When HVAC Door Recalibration is executed.

SET CONDITION
If the span of the passenger blend door is found outside the tolerance.

POSSIBLE CAUSES
- (C33) Passenger blend door driver circuit shorted to ground (will also set overcurrent DTCs)
- (C33) Passenger blend door driver circuit shorted to voltage (will also set overcurrent DTCs)
- (C33) Passenger blend door driver circuit open
- (C34) Common door driver circuit open
- Passenger blend door actuator open
- Passenger blend door actuator broken
- Passenger blend door bound up
- Passenger blend door linkage missing, broken
- A/C heater control

Diagnostic Test

1. RUN THE ACTUATOR CIRCUIT TEST
Turn the ignition on.
With the DRBIII(R) in HVAC, select System Tests and then select Actuator Circuit Test.
Allow the test to run to completion before proceeding.

Q: Does the DRBIII(R) display any Actuator Circuit Test fault messages?

YES: Diagnose and repair the fault(s). Refer to ACTUATOR CIRCUIT TEST DIAGNOSTICS (DUAL-ZONE). Heating & A/C System
NO: Go To 2

2. CHECK FOR DTCS IN THE A/C HEATER CONTROL

NOTE: Diagnose and repair Overcurrent faults before diagnosing Calibration faults.

With the DRBIII(R), read HVAC DTCs.

Q: Does the DRBIII(R) display any DTCs?

YES: Diagnose and repair the DTC(s).
NO: Go To 3

3. CHECK THE RESISTANCE BETWEEN THE (C34) COMMON DOOR DRIVER CIRCUIT & THE C(33) PASSENGER BLEND DOOR DRIVER CIRCUIT



Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Measure the resistance between the (C34) Common Door Driver circuit and the (C33) Passenger Blend Door Driver circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance above 70.0 ohms?

YES: Go To 4
NO: Go To 6

4. CHECK (C33) PASSENGER BLEND DOOR DRIVER CIRCUIT FOR AN OPEN




Disconnect the Passenger Blend Door Actuator harness connector.
Measure the resistance of the (C33) Passenger Blend Door Driver circuit between the A/C Heater Control C1 harness connector and the Passenger Blend Door Actuator harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 5
NO: Repair the (C33) Passenger Blend Door Driver circuit for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

5. CHECK (C34) COMMON DOOR DRIVER CIRCUIT FOR AN OPEN




Measure the resistance of the (C34) Common Door Driver circuit between the A/C Heater Control C1 harness connector and the Passenger Blend Door Actuator harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Replace the Passenger Blend Door Actuator. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the (C34) Common Door Driver circuit for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

6. CHECK FOR A BROKEN PASSENGER BLEND DOOR ACTUATOR
Remove the Passenger Blend Door Actuator from the A/C Heater Housing Assembly.
Disconnect the Passenger Blend Door Actuator harness connector.
By hand, attempt to rotate the actuator in both directions.

Q: Does the actuator turn in either direction?

YES: Replace the Passenger Blend Door Actuator. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 7

7. CHECK FOR MISSING & BROKEN ACTUATOR LINKAGE & THE DOOR FOR BINDING & A LOSS OF RANGE
Inspect the A/C Heater Housing Assembly for missing and broken actuator linkage.
Inspect the linkage and the actuator for broken and missing teeth.
Check the door for binding and a loss of full range.

Q: Are there any physical or mechanical problems with the door, actuator, linkage, or housing?

YES: Repair as necessary. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace the A/C Heater Control. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
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