Page 4993 of 5267

Theory of Operation
The A/C Heater Control drives the Mode Door 2 (Defrost to Floor) Actuator viathe(C801)ModeDoor2Driver
circuit and the (C34) Common Door Driver circuit. All of the door actuatorsshare the (C34) Common Door Driver
circuit. Inside the A/C Heater Control, each door actuator has its own unique driver, but all share a single common
door driver circuit. Due to the shared circuitry similar DTCs can set at thesame time for multiple actuators depend-
ing 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 (C801) Mode Door 2 Driver circuit is shorted to voltage.
Possible Causes
(C801) MODE DOOR 2 DRIVER CIRCUIT SHORTED TO VOLTAGE
A/C HEATER CONTROL
Diagnostic Test
1.CHECK (C801) MODE DOOR 2 DRIVER CIRCUIT FOR A SHORT TO VOLTAGE
Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Turn the ignition on.
Measure the voltage of the (C801) Mode Door 2 Driver circuit.
Is the voltage above 0.2 volts?
Ye s>>
Repair the (C801) Mode Door 2 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: B1048–FLOOR/DEFROST MODE 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 4994 of 5267
Diagnose and repair the other DTC(s). If multiple DTCs are present, beginning with the common circuit,
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 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 4995 of 5267
B1049–FLOOR/DEFROST MODE DOOR CONTROL CIRCUIT OPEN (DUAL-ZONE)
For a complete wiring diagramRefer to Section 8W.
Page 4996 of 5267

Theory of Operation
The A/C Heater Control drives the Mode Door 2 (Defrost to Floor) Actuator viathe(C801)ModeDoor2Driver
circuit and the (C34) Common Door Driver circuit. All of the door actuatorsshare the (C34) Common Door Driver
circuit. Inside the A/C Heater Control, each door actuator has its own unique driver, but all share a single common
door driver circuit. Due to the shared circuitry similar DTCs can set at thesame time for multiple actuators depend-
ing 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 the Mode Door 2 (Defrost to Floor) Actuator’s electrical circuit is open. This DTC has a maturing time of 5
seconds and a de-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
(C801) MODE DOOR 2 DRIVER CIRCUIT OPEN
(C34) COMMON DOOR DRIVER CIRCUIT OPEN
MODE DOOR 2 (DEFROST TO FLOOR) 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 MODE DOOR 2 (DEFROST TO FLOOR) ACTUATOR CIRCUIT RESISTANCE
Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Measure the resistance between the (C801) Mode Door 2 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 4997 of 5267

3.CHECK(C801)MODEDOOR2DRIVERCIRCUITFORANOPEN
Disconnect the Mode Door 2 (Defrost to Floor) Actuator harness con-
nector.
Measure the resistance of the (C801) Mode Door 2 Driver circuit
between the A/C Heater Control C1 harness connector and the Mode
Door 2 (Defrost to Floor) Actuator harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 4
No>>
Repairthe(C801)ModeDoor2Drivercircuitforanopen.
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 Mode
Door 2 (Defrost to Floor) Actuator harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Replace the Mode Door 2 (Defrost to Floor) 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 4998 of 5267
B1049–FLOOR/DEFROST MODE DOOR CONTROL CIRCUIT OPEN (SINGLE-ZONE)
For a complete wiring diagramRefer to Section 8W.
Page 4999 of 5267

Theory of Operation
The A/C Heater Control drives the Mode Door 2 (Defrost to Floor) Actuator viathe(C801)ModeDoor2Driver
circuit and the (C34) Common Door Driver circuit. All of the door actuatorsshare the (C34) Common Door Driver
circuit. Inside the A/C Heater Control, each door actuator has its own unique driver, but all share a single common
door driver circuit. Due to the shared circuitry similar DTCs can set at thesame time for multiple actuators depend-
ing 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 the Mode Door 2 (Defrost to Floor) Actuator’s electrical circuit is open. This DTC has a maturing time of 5
seconds and a de-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
(C801) MODE DOOR 2 DRIVER CIRCUIT OPEN
(C34) COMMON DOOR DRIVER CIRCUIT OPEN
MODE DOOR 2 (DEFROST TO FLOOR) 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 MODE DOOR 2 (DEFROST TO FLOOR) ACTUATOR CIRCUIT RESISTANCE
Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Measure the resistance between the (C801) Mode Door 2 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 5000 of 5267

3.CHECK(C801)MODEDOOR2DRIVERCIRCUITFORANOPEN
Disconnect the Mode Door 2 (Defrost to Floor) Actuator harness con-
nector.
Measure the resistance of the (C801) Mode Door 2 Driver circuit
between the A/C Heater Control C1 harness connector and the Mode
Door 2 (Defrost to Floor) Actuator harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 4
No>>
Repairthe(C801)ModeDoor2Drivercircuitforanopen.
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 Mode
Door 2 (Defrost to Floor) Actuator harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Replace the Mode Door 2 (Defrost to Floor) 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).