Pinpoint Test J: Incorrect/Erratic Direction Of Airflow From Outlets
Climate Control System
Pinpoint Tests
Pinpoint Test J: 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
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 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.
- DTC B226E (Mode Blend Door Motor Stall) - The module senses no change in actuator feedback voltage when the actuator motor has been energized.
- DTC B295E (Mode Door Potentiometer Feedback Circuit Open) - The module senses no voltage drop on the actuator feedback circuit, indicating an open or short to voltage.
- DTC B295F (Mode Door Potentiometer Feedback Circuit short to ground) - The module senses excessive voltage drop on the actuator feedback circuit, indicating a short directly to ground.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Defrost/panel/floor mode door actuator
- HVAC module - Dual Automatic Temperature Control (DATC)
- HVAC module - Electronic Manual Temperature Control (EMTC)
- Stuck or bound linkage or door
PINPOINT TEST J: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS
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J1 CHECK THE AIRFLOW
- Ignition ON.
- Check the airflow in the PANEL, RECIRC, DEFROST and FLOOR modes.
- Is the airflow correct in each setting?
Yes
The system is operating normally.
No
For DATC systems DTC B226E, GO to J7.
For DATC systems DTC B295E or B295F, GO to J2.
For EMTC systems, follow diagnostics for defrost/panel/floor door actuator. GO to J2.
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J2 CHECK THE FEEDBACK POTENTIOMETER TOTAL RESISTANCE
- Disconnect: HVAC Module - DATC C228A or HVAC Module - EMTC C2357A.
- Measure the resistance between:
- For EMTC systems, HVAC module - EMTC C2357A-11, circuit LH111 (BN/WH), harness side and HVAC module - EMTC C2357A-10, circuit RH111 (GY/BU), harness side.
- For DATC systems, HVAC module - DATC C228A-11, circuit LH111 (BN/WH), harness side and HVAC module - DATC C228A-10, circuit RH111 (GY/BU), harness side.
- Is the resistance greater than 500 ohms?
Yes
GO to J4.
No
GO to J3.
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J3 CHECK CIRCUITS RH111 (GY/BU) AND LH111 (BN/WH) 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:
- For EMTC systems, HVAC module - EMTC C2357A-11, circuit LH111 (BN/WH), harness side and HVAC module - EMTC C2357A-10, circuit RH111 (GY/BU), harness side.
- For DATC systems, HVAC module - DATC C228A-11, circuit LH111 (BN/WH), harness side and HVAC module - DATC C228A-10, circuit RH111 (GY/BU), 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 5 ohms.
- Defrost/panel/floor door actuator C2278
- (DATC only) RH temperature 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
CARRY OUT the Temperature Blend Door Actuator component test Temperature Blend Door Actuator on the LH temperature blend 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. If the actuator tests OK, REPAIR circuits LH111 (BN/WH) and RH111 (GY/BU) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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J4 CHECK THE POTENTIOMETER LOW- AND HIGH-SIDE RESISTANCE
- Measure the low-side resistance between:
- For EMTC systems, HVAC module - EMTC C2357A-10, circuit RH111 (GY/BU), harness side and HVAC module - EMTC C2357A-8, circuit VH436 (YE/VT), harness side.
- For DATC systems, HVAC module - DATC C228A-10, circuit RH111 (GY/BU), harness side and HVAC module - DATC C228A-8, circuit VH436 (YE/VT), harness side.
- Measure the high-side resistance between:
- For EMTC systems, HVAC module - EMTC C2357A-11, circuit LH111 (BN/WH), harness side and HVAC module - EMTC C2357A-8, circuit VH436 (YE/VT), harness side.
- For DATC systems, HVAC module - DATC C228A-11, circuit LH111 (BN/WH), harness side and HVAC module - DATC C228A-8, circuit VH436 (YE/VT), harness side.
- Are the resistances between 1,200 and 4,800 ohms?
Yes
GO to J5.
No
CARRY OUT the Defrost/Panel/Floor Mode Door Actuator component test Defrost/Panel/Floor Mode 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. If the actuator tests OK and:
If the low-side resistance only is greater than 4,800 ohms, REPAIR circuit RH111 (GY/BU) 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 1,200 ohms, REPAIR circuits VH436 (YE/VT) and RH111 (GY/BU) 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 4,800 ohms, REPAIR circuit LH111 (BN/WH) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
If thehigh-side resistance only is less than 1,200 ohms, REPAIR circuits VH436 (YE/VT) and LH111 (BN/WH) 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 4,800 ohms, REPAIR circuit VH436 (YE/VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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J5 CHECK CIRCUIT LH111 (BN/WH) OR VH436 (YE/VT) FOR A SHORT TO GROUND
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: Floor/Defrost/Panel Door Actuator C2278.
- Measure the resistance between ground and the following:
- HVAC module - DATC C228A-11 or HVAC module - EMTC C2357A-11, circuit LH111 (BN/WH), harness side.
- HVAC module - DATC C228A-8 or HVAC module - EMTC C2357A-8, circuit VH436 (YE/VT), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to J6.
No
REPAIR circuit LH111 (BN/WH) or circuit VH436 (YE/VT) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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J6 CHECK CIRCUIT RH111 (GY/BU) OR VH436 (YE/VT) FOR A SHORT TO POWER
- Ignition ON.
- Measure the voltage between ground and the following:
- HVAC module - DATC C228A-10 or HVAC module - EMTC C2357A-10, circuit RH111 (GY/BU), harness side.
- HVAC module - DATC C228A-8 or HVAC module - EMTC C2357A-8, circuit VH436 (YE/VT), harness side.
- Is any voltage present?
Yes
REPAIR circuit RH111 (GY/BU) or VH436 (YE/VT) for a short to power. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
For EMTC systems, GO to J7.
For DATC systems, GO to J8.
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J7 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 - EMTC C2357A-10, circuit RH111 (GY/BU), harness side and HVAC module - EMTC C2357A-8, circuit VH436 (YE/VT), harness side.
- Connect a fused jumper wire between:
- HVAC module - EMTC C2357A-13, circuit SBP15 (WH/RD), harness side and HVAC module - EMTC C2357A-19, circuit CH229 (WH/BU), harness side.
- HVAC module - EMTC C2357A-23, circuit GD115 (BK/GY), harness side and HVAC module - EMTC C2357A-20, circuit CH228 (YE/GY), harness side.
- Remove the fused jumpers.
- Connect a fused jumper wire between:
- HVAC module - EMTC C2357A-23, circuit GD115 (BK/GY), harness side and HVAC module - EMTC C2357A-19, circuit CH229 (WH/BU), harness side.
- HVAC module - EMTC C2357A-13, circuit SBP15 (WH/RD), harness side and HVAC module - EMTC C2357A-20, circuit CH228 (YE/GY), 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 J10.
No
GO to J9.
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J8 CHECK THE DOOR ACTUATOR OPERATION
NOTE: If a jumper fuse opens while carrying out this test step, repair the circuit(s) for a short.
- Disconnect: HVAC Module - DATC C228A.
- With the fused jumper connections made as directed below, measure the resistance between HVAC module - DATC C228A-10, circuit RH111 (GY/BU), harness side and HVAC module - DATC C228A-8, circuit VH436 (YE/VT), harness side.
- Connect a fused jumper wire between:
- HVAC module - DATC C228A-13, circuit SBP15 (WH/RD), harness side and HVAC module - DATC C228A-19, circuit CH229 (WH/BU), harness side.
- HVAC module - DATC C228A-23, circuit GD115 (BK/GY), harness side and HVAC module - DATC C228A-20, circuit CH228 (YE/GY), harness side.
- Remove the fused jumpers.
- Connect a fused jumper wire between:
- HVAC module - DATC C228A-23, circuit GD115 (BK/GY), harness side and HVAC module - DATC C228A-19, circuit CH229 (WH/BU), harness side.
- HVAC module - DATC C228A-13, circuit SBP15 (WH/RD), harness side and HVAC module - DATC C228A-20, circuit CH228 (YE/GY), 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, CARRY OUT the Defrost/Panel/Floor Door Actuator component test Defrost/Panel/Floor Mode 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. If the actuator tests OK, GO to J10.
No
GO to J9.
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J9 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.
- Disconnect: Defrost/Panel/Floor Door Actuator C2278.
- Measure the resistance between HVAC module - DATC C228A-20 or HVAC module - EMTC C2357A-20, circuit CH228 (YE/GY), harness side and defrost/panel/floor door actuator C2278-7, circuit (GY/BK), harness side.
- Measure the resistance between HVAC module - DATC C228A-19 or HVAC module - EMTC C2357A-19, circuit CH229 (WH/BU), harness side and defrost/panel/floor door actuator C2278-6, circuit (BU), harness side.
- Are the resistances less than 5 ohms?
Yes
INSPECT for binding or broken linkage. REPAIR as necessary. If no condition is found, INSTALL a new 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. TEST the system for normal operation.
No
REPAIR the circuit(s) for an open. TEST the system for normal operation.
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J10 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 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 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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