Page 4865 of 5267

Theory of Operation
The A/C Heater Control drives the Left Blend Door Actuator via the (C61) Blend Door Driver circuit and the (C34)
Common Door Driver circuit. All of the door actuators share the (C34) Common Door Driver circuit. Inside the A/C
Heater Control, each door actuator has its own unique driver, but all sharea single common door driver circuit. Due
to the shared circuitry similar DTCs can set at the same time for multiple actuators depending upon the type of
short, its location, and the direction the actuator is moving when the short is present.
When Monitored:
When the Actuator DTC Detection Test is executed.
Set Condition:
If the (C61) Blend Door Driver circuit is shorted to voltage.
Possible Causes
(C61) BLEND DOOR DRIVER CIRCUIT SHORTED TO VOLTAGE
A/C HEATER CONTROL
Diagnostic Test
1.CHECK (C61) BLEND DOOR DRIVER CIRCUIT FOR A SHORT TO VOLTAGE
NOTE: If present, diagnose and repair DTC B10AB Right Blend
Door Control Circuit High or B10AA Right Blend Door Control Cir-
cuit Low before proceeding.
Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Turn the ignition on.
Measure the voltage of the (C61) Blend Door Driver circuit.
Is the voltage above 0.2 volts?
Ye s>>
Repair the (C61) Blend Door Driver circuit for a short to
voltage.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
No>>
Go To 2
2.RUN THE ACTUATOR DTC DETECTION TEST
Turn the ignition off.
Reconnect the A/C Heater Control C1 harness connector.
Turn the ignition on.
With the scan tool in HVAC, select System Tests and then select Actuator DTCDetection. When the test is com-
plete, select View DTCs.
Does the scan tool only display: B10A4–LEFT BLEND DOOR CONTROL CIRCUIT HIGH?
Ye s>>
Replace the A/C Heater Control in accordance with the Service Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).
No, Other DTC(s) Displayed
Page 4866 of 5267
Diagnose and repair the DTC(s). If multiple DTCs are present, beginning with the passenger blend door,
diagnose and repair all short high DTCs and then all short low DTCs. Refer tothe Table of Contents in
this Section for a complete list of HVAC related symptoms.
No, And No Other DTCs Displayed
Using the wiring diagram as a guide, inspect the wiring and connectors for conditions causing an inter-
mittent short. Repair as necessary.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).
Page 4867 of 5267
B10A5–LEFT BLEND DOOR CONTROL CIRCUIT OPEN (DUAL-ZONE)
For a complete wiring diagramRefer to Section 8W.
Page 4868 of 5267

Theory of Operation
The A/C Heater Control drives the Left Blend Door Actuator via the (C61) Blend Door Driver circuit and the (C34)
Common Door Driver circuit. All of the door actuators share the (C34) Common Door Driver circuit. Inside the A/C
Heater Control, each door actuator has its own unique driver, but all sharea single common door driver circuit. Due
to the shared circuitry similar DTCs can set at the same time for multiple actuators depending upon the location of
the open circuit and the direction the actuator is moving when the open is present.
When Monitored:
During actuator calibration.
Set Condition:
If Left Blend Door Actuator’s electrical circuit is open. This DTC has a maturingtimeof5secondsandade-
maturing time of 10 seconds. If the DTC’s status changes from active to stored it will stay in memory for 100
ignition cycles.
Possible Causes
(C61) BLEND DOOR DRIVER CIRCUIT OPEN
(C34) COMMON DOOR DRIVER CIRCUIT OPEN
LEFT BLEND DOOR ACTUATOR
A/C HEATER CONTROL
NOTE: This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC
is stored. Refer to HVAC System Test for stored DTC test procedures.
Diagnostic Test
1.CHECK FOR ACTIVE CONTROL CIRCUIT/PERFORMANCE DTCs
Turn the ignition on.
With the scan tool, read active HVAC DTCs.
Does the scan tool display any active: XXXX CONTROL CIRCUIT/PERFORMANCE DTCs?
Ye s>>
Diagnose and repair the DTC(s). Refer to the Table of Contents in this Section for a complete list of
HVAC related symptoms.
No>>
Go To 2
2.CHECK LEFT BLEND DOOR ACTUATOR CIRCUIT RESISTANCE
Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Measure the resistance between the (C61) Blend Door Driver circuit
and the (C34) Common Door Driver circuit in the A/C Heater Control C1
harness connector.
Is the resistance above 70 ohms?
Ye s>>
Go To 3
No>>
Replace the A/C Heater Control in accordance with the Ser-
vice Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
Page 4869 of 5267

3.CHECK (C61) BLEND DOOR DRIVER CIRCUIT FOR AN OPEN
Disconnect the Left Blend Door Actuator harness connector.
Measure the resistance of the (C61) Blend Door Driver circuit between
the A/C Heater Control C1 harness connector and the Left Blend Door
Actuator harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 4
No>>
Repair the (C61) Blend Door Driver circuit for an open.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
4.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 Left
Blend Door Actuator harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Replace the Left Blend Door Actuator in accordance with
the Service Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
No>>
Repair the (C34) Common Door Driver circuit for an open.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
Page 4870 of 5267

B10A6–LEFT BLEND DOOR TRAVEL RANGE TOO SMALL (DUAL-ZONE)
For a complete wiring diagramRefer to Section 8W.
Theory of Operation
The A/C Heater Control calibrates each actuator individually. Automaticcalibration occurs upon power up after
installing a new A/C Heater Control. Manual calibration occurs by sendinga command with the scan tool. The pur-
pose 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 an end 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 less than the expected range for this actuator, this DTC will set. Note thatthe control clears all
stored calibration faults at the beginning of the calibration procedure.
When Monitored:
During actuator calibration.
Set Condition:
If the total span of the Left Blend Door is less than the low range limit.
Possible Causes
DOOR DRIVER ELECTRICAL CIRCUIT(S)
LEFT BLEND DOOR SEIZED, BINDING, OBSTRUCTED
LEFT BLEND DOOR ACTUATOR
A/C HEATER CONTROL
Diagnostic Test
1.CHECK FOR ACTIVE CONTROL CIRCUIT/PERFORMANCE DTCs
Turn the ignition on.
With the scan tool, read active HVAC DTCs.
Does the scan tool display any active: XXXX CONTROL CIRCUIT/PERFORMANCE DTCs?
Ye s>>
Diagnose and repair the DTC(s). Refer to the Table of Contents in this Section for a complete list of
HVAC related symptoms.
No>>
Go To 2
2.CHECK FOR ACTIVE CONTROL CIRCUIT OPEN DTCs
With the scan tool, read active HVAC DTCs.
Does the scan tool display any active: XXXX CONTROL CIRCUIT OPEN DTCs?
Ye s>>
Diagnose and repair the DTC(s). Refer to the Table of Contents in this Section for a complete list of
HVAC related symptoms.
No>>
Go To 3
3.RUN THE ACTUATOR DTC DETECTION TEST
With the scan tool in HVAC, select System Tests and then select Actuator DTCDetection. When the test is com-
plete, select View DTCs.
Does the scan tool display any DTCs?
Ye s>>
Diagnose and repair the DTC(s). If multiple DTCs are present, beginning with the passenger blend door,
diagnose and repair all short high DTCs and then all short low DTCs. Refer tothe Table of Contents in
this Section for a complete list of HVAC related symptoms.
No>>
Go To 4
Page 4871 of 5267

4.INSPECT ACTUATOR & HOUSING ASSEMBLY FOR A CONDITION CAUSING THE DOOR TO SEIZE OR
BIND
Turn the ignition off.
Inspect the actuator, linkage, and housing assembly for a condition causing the door to seize or bind.
Are there any physical or mechanical problems with the door, housing, linkage, or actuator?
Ye s>>
Repair as necessary in accordance with the Service Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).
No>>
Go To 5
5.CHECK LEFT BLEND DOOR TRAVEL
Remove the Left Blend Door Actuator from the A/C Heater Housing Assembly.
By hand, attempt to rotate the door in both directions. The door should operate smoothly in both directions over
approximately 53 degrees of travel.
Does the door operate smoothly in both directions over approximately 53 degrees of travel?
Ye s>>
Replace the Left Blend Door Actuator in accordance with the Service Information. Then, Go To 6.
No>>
Repair as necessary in accordance with the Service Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).
6.RUN ACTUATOR CALIBRATION TEST
Turn the ignition on.
With the scan tool, select System Tests and then select Actuator Calibration Test. When the test is complete, select
View DTCs.
Does the scan tool display: B10A6–LEFT BLEND DOOR TRAVEL RANGE TOO SMALL?
Ye s>>
Replace the A/C Heater Control in accordance with the Service Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).
No>>
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).
Page 4872 of 5267

B10A7–LEFT BLEND DOOR TRAVEL RANGE TOO LARGE (DUAL-ZONE)
For a complete wiring diagramRefer to Section 8W.
Theory of Operation
The A/C Heater Control calibrates each actuator individually. Automaticcalibration occurs upon power up after
installing a new A/C Heater Control. Manual calibration occurs by sendinga command with the scan tool. The pur-
pose 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 an end 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 exceeds the expected range for this actuator, this DTC will set. Note that the control clears all
stored calibration faults at the beginning of the calibration procedure.
When Monitored:
During actuator calibration.
Set Condition:
If the total span of the Left Blend Door exceeds the high range limit.
Possible Causes
DOOR DRIVER ELECTRICAL CIRCUIT(S)
LEFT BLEND DOOR OR A/C HEATER HOUSING COMPONENTS WARPED, WORN, DAMAGED, MISSING,
BROKEN
LEFT BLEND DOOR ACTUATOR
A/C HEATER CONTROL
Diagnostic Test
1.CHECK FOR ACTIVE CONTROL CIRCUIT/PERFORMANCE DTCs
Turn the ignition on.
With the scan tool, read active HVAC DTCs.
Does the scan tool display any active: XXXX CONTROL CIRCUIT/PERFORMANCE DTCs?
Ye s>>
Diagnose and repair the DTC(s). Refer to the Table of Contents in this Section for a complete list of
HVAC related symptoms.
No>>
Go To 2
2.CHECK FOR ACTIVE CONTROL CIRCUIT OPEN DTCs
With the scan tool, read active HVAC DTCs.
Does the scan tool display any active: XXXX CONTROL CIRCUIT OPEN DTCs?
Ye s>>
Diagnose and repair the DTC(s). Refer to the Table of Contents in this Section for a complete list of
HVAC related symptoms.
No>>
Go To 3