Pinpoint Test L: Incorrect/Erratic Direction Of Airflow From Outlets
Climate Control System
Pinpoint Test L: Incorrect/Erratic Direction of Airflow From Outlets
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, to rotate the panel/defrost and floor mode door actuator, the HVAC module supplies voltage and ground to the panel/defrost and floor mode door actuator motor through the actuator motor circuits. To reverse the panel/defrost and floor mode door actuator rotation, the HVAC module reverses the voltage and ground circuits.
The panel/defrost and 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 panel/defrost and floor mode door actuator feedback circuit to determine the panel/defrost and floor mode door actuator position by the position of the actuator feedback resistor wiper arm.
Depending on the climate control mode setting, the panel/defrost mode door directs the airflow to either the panel or defrost ducts when the floor mode door is closed. When the floor mode door is open, airflow is interrupted to the panel/defrost mode door and directed through the floor vents. For split or blended airflow, the HVAC module can stop either mode door actuator in mid-position using the feedback resistor to indicate when it has reached that position.
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.
- DTC B1263 (Servo Motor Vent Circuit Failure) - The module senses no change in actuator feedback voltage when the actuator motor has been energized.
- DTC B1264 (Servo Motor Foot Circuit Failure) - The module senses no change in actuator feedback voltage when the actuator motor has been energized.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Panel/defrost or floor door actuator
- HVAC module
- Stuck or bound linkage or door
PINPOINT TEST L: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS
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L1 CHECK THE FEEDBACK POTENTIOMETER TOTAL RESISTANCE
- Disconnect: HVAC Module C228A.
- Disconnect: HVAC Module C228B.
- Measure the resistance between HVAC module C228B-8, circuit 436 (RD/LG), harness side and HVAC module C228A-20, circuit 438 (RD/WH), harness side.
- Is the resistance greater than 500 ohms?
Yes
If diagnosing DTC B1263, GO to L3.
If diagnosing DTC B1264, GO to L4.
No
GO to L2.
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L2 CHECK POTENTIOMETER FEEDBACK CIRCUITS 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.
- Measure the resistance between HVAC module C228B-8, circuit 436 (RD/LG), harness side and HVAC module C228A-20, circuit 438 (RD/WH), harness side.
- While measuring the resistance above, disconnect the following components one at a time, in order. Stop disconnecting components if the measured resistance rises above 500 ohms.
- Air inlet door actuator C289
- LH blend door actuator C2092
- RH blend door actuator C2092
- Did the resistance rise above 500 ohms?
Yes
INSTALL a new actuator (the last one to be disconnected). CONNECT the actuator electrical connectors before the HVAC module connectors. 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.
No
Visually INSPECT the harness between the actuators and the HVAC module for obvious damage. REPAIR as necessary. If no damage is evident, INSTALL a new floor door actuator and panel/defrost door actuator. If a new actuator is installed, CONNECT the actuator electrical connectors before the HVAC module connectors. 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.
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L3 CHECK POTENTIOMETER LOW- AND HIGH-SIDE RESISTANCE
- Measure the low-side resistance between HVAC module C228A-20, circuit 438 (RD/WH), harness side and HVAC module C228B-15, circuit 1123 (YE/WH), harness side.
- Measure the high-side resistance between HVAC module C228B-8, circuit 436 (RD/LG), harness side and HVAC module C228B-15, circuit 1123 (YE/WH), harness side.
- Is the resistance between 250 and 5,500 ohms?
Yes
GO to L5.
No
CARRY OUT the Panel/Defrost 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 and: Component Tests and General Diagnostics
If the low-side resistance only is greater than 5,500 ohms, REPAIR circuit 438 (RD/WH) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
If the low-side resistance only is less than 250 ohms, REPAIR circuits 1123 (YE/WH) and 438 (RD/WH) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
If the high-side resistance only is greater than 5,500 ohms, REPAIR circuit 436 (RD/LG) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
If thehigh-side resistance only is less than 250 ohms, REPAIR circuits 1123 (YE/WH) and 436 (RD/LG) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
If both thehigh-side and low-side resistance is greater than 5,500 ohms, REPAIR circuit 1123 (YE/WH) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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L4 CHECK POTENTIOMETER LOW- AND HIGH-SIDE RESISTANCE
- Measure the low-side resistance between HVAC module C228A-20, circuit 438 (RD/WH), harness side and HVAC module C228B-14, circuit 1130 (PK/LG), harness side.
- Measure the high-side resistance between HVAC module C228B-8, circuit 436 (RD/LG), harness side and HVAC module C228B-14, circuit 1130 (PK/LG), harness side.
- Is the resistance between 250 and 5,500 ohms?
Yes
GO to L5.
No
CARRY OUT the 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 and: Component Tests and General Diagnostics
If the low-side resistance only is greater than 5,500 ohms, REPAIR circuit 438 (RD/WH) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
If the low-side resistance only is less than 250 ohms, REPAIR circuits 1130 (PK/LG) and 438 (RD/WH) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
If the high-side resistance only is greater than 5,500 ohms, REPAIR circuit 436 (RD/LG) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
If thehigh-side resistance only is less than 250 ohms, REPAIR circuits 1130 (PK/LG) and 436 (RD/LG) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
If both thehigh-side and low-side resistance is greater than 5,500 ohms, REPAIR circuit 1130 (PK/LG) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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L5 CHECK CIRCUITS 438 (RD/WH), 1123 (YE/WH) AND 1130 (PK/LG) FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between ground and:
- HVAC module C228A-20, circuit 438 (RD/WH), harness side.
- For DTC B1263, HVAC module C228B-15, circuit 1123 (YE/WH), harness side.
- For DTC B1264, HVAC module C228B-14, circuit 1130 (PK/LG), harness side.
- Is any voltage present?
Yes
REPAIR circuit 438 (RD/WH), 1123 (YE/WH) or 1130 (PK/LG) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to L6.
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L6 CHECK CIRCUITS 436 (RD/LG), 1123 (YE/WH) AND 1130 (PK/LG) FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between ground and:
- HVAC module C228B-8, circuit 436 (RD/LG), harness side.
- For DTC B1263, HVAC module C228B-15, circuit 1123 (YE/WH), harness side.
- For DTC B1264, HVAC module C228B-14, circuit 1130 (PK/LG), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
If diagnosing DTC B1263, GO to L7.
If diagnosing DTC B1264, GO to L8.
No
REPAIR circuit 436 (RD/LG), 1123 (YE/WH) or 1130 (PK/LG) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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L7 CHECK THE DOOR ACTUATOR OPERATION
NOTE: If a jumper fuse opens while carrying out this test step, repair the circuit(s) for a short.
- Ignition ON.
- With the fused jumper connections made as directed below, measure the resistance between HVAC module C228A-20, circuit 438 (RD/WH), harness side and HVAC module C228B-15, circuit 1123 (YE/WH), harness side.
- Connect a fused jumper wire between:
- HVAC module C228A-25, circuit 1380 (TN/YE), harness side and HVAC module C228B-11, circuit 1566 (RD/YE), harness side.
- HVAC module C228A-24, circuit 1379 (PK/LB), harness side and HVAC module C228A-2, circuit 57 (BK), harness side.
- Remove the fused jumpers.
- Connect a fused jumper wire between:
- HVAC module C228A-24, circuit 1379 (PK/LB), harness side and HVAC module C228B-11, circuit 1566 (RD/YE), harness side.
- HVAC module C228A-25, circuit 1380 (TN/YE), harness side and HVAC module C228A-2, circuit 57 (BK), harness side.
- Does the resistance smoothly increase and/or decrease when the jumpers are connected?
Yes
INSPECT for broken door and linkage. REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If no condition is found, GO to L11.
No
GO to L9.
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L8 CHECK THE DOOR ACTUATOR OPERATION
NOTE: If a jumper fuse opens while carrying out this test step, repair the circuit(s) for a short.
- Ignition ON.
- With the fused jumper connections made as directed below, measure the resistance between HVAC module C228A-20, circuit 438 (RD/WH), harness side and HVAC module C228B-14, circuit 1130 (PK/LG), harness side.
- Connect a fused jumper wire between:
- HVAC module C228A-23, circuit 1376 (BK/LB), harness side and HVAC module C228B-11, circuit 1566 (RD/YE), harness side.
- HVAC module C228A-22, circuit 1375 (PK/YE), harness side and HVAC module C228A-2, circuit 57 (BK), harness side.
- Remove the fused jumpers.
- Connect a fused jumper wire between:
- HVAC module C228A-22, circuit 1375 (PK/YE), harness side and HVAC module C228B-11, circuit 1566 (RD/YE), harness side.
- HVAC module C228A-23, circuit 1376 (BK/LB), harness side and HVAC module C228A-2, circuit 57 (BK), harness side.
- Does the resistance smoothly increase and/or decrease when the jumpers are connected?
Yes
INSPECT for broken door and linkage. REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If no condition is found, GO to L11.
No
GO to L9.
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L9 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: For DTC B1263, Panel/Defrost Door Actuator C2248.
- Disconnect: For DTC B1264, Floor Door Actuator C234.
For DTC B1263
- For DTC B1263, measure the resistance between HVAC module C228A-24, circuit 1379 (PK/LB), harness side and panel/defrost door actuator C2248-1, circuit 1379 (PK/LB), harness side.
For DTC B1263
- For DTC B1263, measure the resistance between HVAC module C228A-25, circuit 1380 (TN/YE), harness side and panel/defrost door actuator C2248-6, circuit 1380 (TN/YE), harness side.
For DTC B1264
- For DTC B1264, measure the resistance between HVAC module C228A-22, circuit 1375 (PK/YE), harness side and floor door actuator C234-1, circuit 1375 (PK/YE), harness side.
For DTC B1264
- For DTC B1264, measure the resistance between HVAC module C228A-23, circuit 1376 (BK/LB), harness side and floor door actuator C234-6, circuit 1376 (BK/LB), harness side.
- Are the resistances less than 5 ohms?
Yes
INSPECT for broken door and linkage. REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If no condition is found, GO to L10.
No
REPAIR the circuit(s) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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L10 CHECK THE ACTUATOR CONNECTION
- Disconnect the actuator connector.
- Check for:
- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat the actuator connector.
- Clear the DTCs.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new floor door actuator and panel/defrost door actuator. If a new actuator is installed, CONNECT the actuator electrical connectors before the HVAC module connectors. 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.
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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L11 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.
- Inspect the 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 and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new HVAC module. REFER to Climate Control Service and Repair. 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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