Pinpoint Test L: Incorrect/Erratic Direction of Airflow From Outlets
Climate Control System
Pinpoint Tests
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
The panel/defrost and floor door actuator motors both work the same. Each door actuator motor has 2 circuits that the HVAC module applies voltage to and reverses the polarity to reverse door actuator motor rotation. The panel/defrost door actuator motor circuits are 1379 (PK/LB) and 1380 (TN/YE); the floor door actuator motor circuits are 1375 (PK/YE) and 1376 (BK/LB). Each door actuator motor has a position sensor that supplies a voltage to the HVAC module to indicate door position. Both door actuator motors receive reference voltage (5V) on circuit 436 (RD/LG) and a sensor ground on circuit 438 (RD/WH). Position signals are provided by the panel/defrost door actuator motor on circuit 1123 (YE/WH) and circuit 1130 (PK/LG) by the floor door actuator motor.
- 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 THE FEEDBACK POTENTIOMETER TOTAL RESISTANCE
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). 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. Panel/Defrost Door Actuator If the actuator tests OK and:
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. Floor Door Actuator If the actuator tests OK and:
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 circuits 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.
- 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. 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.
- 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. 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.
DTC B1263
- NOTE: For DTC B1263 only.
- 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.
DTC B1263
- NOTE: For DTC B1263 only.
- 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.
DTC B1264
- NOTE: For DTC B1264 only.
- 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.
DTC B1264
- NOTE: For DTC B1264 only.
- 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. 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. 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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