Pinpoint Test F: Incorrect/Erratic Direction Of Airflow From Outlets
Climate Control System
Pinpoint Tests
Pinpoint Test F: Incorrect/Erratic Direction Of Airflow From Outlets
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, to rotate the defrost/panel/floor mode door actuator, the HVAC module supplies voltage and ground to the defrost/panel/floor mode door actuator motor through the actuator motor circuits. To reverse the defrost/panel/floor mode door actuator rotation, the HVAC module reverses the voltage and ground circuits.
The defrost/panel/floor mode door actuator feedback resistor is supplied a 5-volt reference voltage and ground from the HVAC module. The HVAC module measures the resistance on the defrost/panel/floor mode door actuator feedback circuit to determine the defrost/panel/floor mode door actuator position by the position of the actuator feedback resistor wiper arm.
During an actuator calibration cycle, the HVAC module drives the defrost/panel/floor mode door until the door reaches both internal stops in the HVAC case. If the defrost/panel/floor mode door is temporarily obstructed or binding during a calibration cycle, the HVAC module may interpret this as the actual end of travel for the door. When this condition occurs and the HVAC module commands the actuator to its end of travel, the airflow may not be from the expected outlets.
B12A4-B298B:
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Mode door actuator
- HVAC module
- Stuck or damaged linkage or door
PINPOINT TEST F: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS
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F1 CHECK THE HVAC MODULE FOR DTCs
- Ignition ON.
- Check the HVAC module for DTCs.
- Are DTCs present?
Yes
For DTC B12A7, INSPECT for binding/damaged linkage or door. REPAIR as necessary. If no condition is found, INSTALL a new floor/defrost/panel door actuator. If a new actuator is installed, CONNECT the actuator electrical connector before the HVAC module connector(s). This will allow the new actuator to be calibrated when the HVAC module is reconnected. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
For DTC B12A4, GO to F2.
For DTC B298A, GO to F3.
For DTC B298B, GO to F4.
For DTC B12A5, GO to F6.
For DTC B12A6, GO to F10.
No
INSPECT for broken actuator drive shaft, cam or door. REPAIR as necessary. If no condition is found, GO to F13.
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F2 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO POWER
- Ignition OFF.
- Disconnect: HVAC Module C2357A.
- Ignition ON.
- Measure the voltage between ground and:
- HVAC module C2357A-19, circuit CH228 (YE/GY), harness side.
- HVAC module C2357A-20, circuit CH229 (WH/BU), harness side.
- Are any voltages present?
Yes
REPAIR circuit CH228 (YE/GY) or CH229 (WH/BU) for a short to power. TEST the system for normal operation.
No
GO to F5.
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F3 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR AN OPEN
NOTE: Access to the connector in the following step is difficult. Before performing this step, visually inspect the actuator and its harness for obvious damage. If no damage is evident, proceed with the test.
- Ignition OFF.
- Disconnect: HVAC Module C2357A.
- Disconnect: Defrost/Panel/Floor Door Actuator C2278.
- Measure the resistance between HVAC module C2357A-19, circuit CH228 (YE/GY), harness side and defrost/panel/floor door actuator C2278-6, circuit CH228 (YE/GY), harness side.
- Measure the resistance between HVAC module C2357A-20, circuit CH229 (WH/BU), harness side and defrost/panel/floor door actuator C2278-5, circuit CH229 (WH/BU).
- Are the resistances less than 5 ohms?
Yes
GO to F13.
No
REPAIR circuit CH228 (YE/GY) or CH229 (WH/BU) for an open. TEST the system for normal operation.
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F4 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: HVAC Module C2357A.
- Measure the resistance between ground and:
- HVAC module C2357A-19, circuit CH228 (YE/GY), harness side.
- HVAC module C2357A-20, circuit CH229 (WH/BU), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to F5.
No
REPAIR circuit CH228 (YE/GY) or CH229 (WH/BU) for a short to ground. TEST the system for normal operation.
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F5 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TOGETHER
- Ignition OFF.
- Disconnect: Defrost/Panel/Floor Door Actuator C2278.
- Measure the resistance between HVAC module C2357A-19, circuit CH228 (YE/GY), harness side and HVAC module C2357A-20, circuit CH229 (WH/BU), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to F13.
No
REPAIR circuits CH228 (YE/GY) and CH229 (WH/BU) for a short together. TEST the system for normal operation.
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F6 CHECK CIRCUIT VH436 (YE/VT) FOR AN OPEN
NOTE: Access to the connector in the following step is difficult. Before performing this step, visually inspect the actuator and its harness for obvious damage. If no damage is evident, proceed with the test.
- Ignition OFF.
- Disconnect: HVAC Module C2357A.
- Disconnect: Defrost/Panel/Floor Door Actuator C2278.
- Measure the resistance between HVAC module C2357A-8, circuit VH436 (YE/VT), harness side and defrost/panel/floor door actuator C2278-2, circuit VH436 (YE/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
CARRY OUT the Defrost/Panel/Floor Door actuator component test. If a new actuator is installed, CONNECT the actuator electrical connector before the HVAC module connector(s). This will allow the new actuator to be calibrated when the HVAC module is reconnected. If the actuator tests OK, GO to F7. Defrost/Panel/Floor Door Actuator
No
REPAIR circuit VH436 (YE/VT) for an open. TEST the system for normal operation.
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F7 CHECK CIRCUIT VH436 (YE/VT) FOR A SHORT TO POWER
- Ignition ON.
- Measure the voltage between ground and HVAC module C2357A-8, circuit VH436 (YE/VT), harness side.
- Is any voltage present?
Yes
REPAIR circuit VH436 (YE/VT) for a short to power. TEST the system for normal operation.
No
GO to F8.
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F8 CHECK CIRCUITS LH111 (BN/WH) AND VH436 (YE/VT) FOR A SHORT TOGETHER
- Ignition OFF.
- Measure the resistance between HVAC module C2357A-11, circuit LH111 (BN/WH), harness side and HVAC module C2357A-8, circuit VH436 (YE/VT), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to F9.
No
REPAIR circuits LH111 (BN/WH) and VH436 (YE/VT) for a short together. TEST the system for normal operation.
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F9 CHECK THE ACTUATOR RETURN CIRCUIT RH111 (GY/BU) FOR AN OPEN
- Measure the resistance between HVAC module C2357A-10, circuit RH111 (GY/BU), harness side and defrost/panel/floor door actuator C2278-1, circuit RH111 (GY/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to F13.
No
REPAIR circuit RH111 (GY/BU) for an open. TEST the system for normal operation.
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F10 CHECK CIRCUIT VH436 (YE/VT) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: HVAC Module C2357a.
- Measure the resistance between ground and HVAC module C2357A-8, circuit VH436 (YE/VT), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to F11.
No
REPAIR circuit VH436 (YE/VT) for a short to ground. TEST the system for normal operation.
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F11 CHECK CIRCUITS RH111 (GY/BU) AND VH436 (YE/VT) FOR A SHORT TOGETHER
NOTE: Access to the connector in the following step is difficult. Before performing this step, visually inspect the actuator and its harness for obvious damage. If no damage is evident, proceed with the test.
- Disconnect: Defrost/Panel/Floor Door Actuator C2278.
- Measure the resistance between HVAC module C2357A-10, circuit RH111 (GY/BU), harness side and HVAC module C2357A-8, circuit VH436 (YE/VT), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to F12.
No
REPAIR circuits RH111 (GY/BU) and VH436 (YE/VT) for a short together. TEST the system for normal operation.
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F12 CHECK CIRCUIT LH111 (BN/WH) FOR AN OPEN
- Measure the resistance between HVAC module C2357A-11, circuit LH111 (BN/WH), harness side and defrost/panel/floor door actuator C2278-3, circuit LH111 (BN/WH), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to F13.
No
REPAIR circuit LH111 (BN/WH) for an open. TEST the system for normal operation.
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F13 CHECK THE ACTUATOR CONNECTION
- Disconnect the actuator connector.
- Check for:
- corrosion.
- pushed-out connectors.
- incorrectly seated connector.
- Connect and correctly seat the actuator connector.
- Carry out the HVAC Module Cold Boot Process.
- Operate the system.
- Does the concern return?
Yes
CARRY OUT the Defrost/Panel/Floor Door Actuator component test. If a new actuator is installed, CONNECT the actuator electrical connector before the HVAC module connector(s). This will allow the new actuator to be calibrated when the HVAC module is reconnected. If the actuator tests OK, GO to F14. Defrost/Panel/Floor Door Actuator
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. TEST the system for normal operation.
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F14 MODULE ACTUATOR POSITION CALIBRATION
NOTE: The purpose of the module actuator position calibration is to allow the HVAC module to reinitialize and calibrate the actuator stop points. To carry out the calibration, follow the steps below.
- Ignition OFF.
- Disconnect and inspect the HVAC module connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the HVAC module connectors.
- Ignition ON.
- Clear the DTCs.
- Select any position except OFF.
- NOTE: The HVAC module will now initialize and calibrate the actuators. Calibration of the actuators will take approximately 30 seconds.
- Operate the system.
- Enter the following diagnostic mode on the scan tool: Self Test - HVAC Module.
- Is the concern still present or the DTCs return?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
No
The system is now operating correctly at this time. The concern may have been caused by a foreign object in the HVAC case or temporary binding that restricted actuator door travel. CHECK any actuator external linkage. If condition recurs,
INSPECT actuator linkage and door for binding and CHECK HVAC case for foreign objects.
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