Pinpoint Test H: Incorrect/Erratic Direction Of Airflow From Outlets

Climate Control System

Pinpoint Test H: Incorrect/Erratic Direction of Airflow From Outlets

Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information Electrical Diagrams.

Normal Operation

The HVAC module supplies voltage and ground to the defrost/panel/floor mode door actuator motor through the actuator motor circuits to rotate the defrost/panel/floor mode door actuator. To reverse the defrost/panel/floor mode door actuator rotation, the HVAC module reverses voltage and ground on the 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 3-1 (Mode Feedback Circuit/Performance)- The module senses no changes in the feedback circuit when motor movement is commanded and no motor electrical DTCs are present. This indicates an open actuator motor, an open or shorted feedback circuit, an open feedback resistor reference voltage circuit, or an internal electrical or mechanical failure.

- DTC 3-2 (Mode Motor Driver Circuit/Performance)- The module senses lower than expected voltage on an actuator motor circuit when voltage is applied to drive the motor. This indicates a short to ground or the module senses greater than expected voltage on the actuator motor circuit when ground is applied to drive the motor, indicating a short to voltage.

- DTC 3-3 (Mode Actuator Calibration Performance)- The module senses the actuator has moved outside its travel limits during calibration. This indicates broken/disconnected linkage or door or an internal mechanical failure.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Defrost/panel/floor mode door actuator

- HVAC module

- Defrost/panel/floor mode door binding or stuck

PINPOINT TEST H : INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS

H1 CHECK THE HVAC MODULE FOR DTCs

NOTE: If HVAC DTC 4-4 is present, GO to Pinpoint Test D and diagnose that DTC first Pinpoint Test D: DTC 4-4.

- Ignition ON.

- CARRY OUT the HVAC module self-test.

- Check for HVAC DTCs retrieved during the self-test.

Are HVAC DTCs present?

Yes

For DTC 3-1, GO to H2.

For DTC 3-2, GO to H9.

For DTC 3-3, GO to H8.

No
GO to H7.

H2 CHECK THE ACTUATOR MOTOR AND CIRCUITS

- Ignition OFF.

- Disconnect: HVAC Module C228A.

- Measure the resistance between HVAC module C228A-7, circuit CH202 (BU/GN), harness side and HVAC module C228A-8, circuit CH203 (GN/BN), harness side.





Is the resistance less than 40 ohms?

Yes
GO to H4.

No
GO to H3.

H3 CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR

- Ignition OFF.

- Disconnect: Defrost/Panel/Floor Mode Door Actuator C236.

- CARRY OUT the Defrost/Panel/Floor Mode Door Actuator component test Component Tests.

Did the defrost/panel/floor mode door actuator test OK?

Yes
REPAIR circuit CH202 (BU/GN) or CH203 (GN/BN) for an open or high resistance. REPEAT the self-test. TEST the system for normal operation.

No
GO to H13.

H4 CHECK THE POTENTIOMETER LOW- AND HIGH-SIDE RESISTANCE

- Measure the high-side resistance between HVAC module C228A-12, circuit CH232 (WH/BN), harness side and HVAC module C228A-1, circuit CH204 (GY/OG), harness side.





- Measure the low-side resistance between HVAC module C228A-2, circuit CH233 (VT/BN), harness side and HVAC module C228A-1, circuit CH204 (GY/OG), harness side.





Are the resistances between 215 and 4,375 ohms?

Yes
GO to H5.

No
CARRY OUT the Defrost/Panel/Floor Mode Door Actuator component test Component Tests. INSTALL a new defrost/panel/floor mode door actuator if necessary.

If the actuator tests OK and:

If the high-side resistance only is greater than 4,375 ohms, REPAIR circuit CH232 (WH/BN) for an open.

If the high-side resistance only is less than 215 ohms, REPAIR circuits CH204 (GY/OG) and CH232 (WH/BN) for a short together.

If the low-side resistance only is greater than 4,375 ohms, REPAIR circuit CH233 (VT/BN) for an open.

If thelow-side resistance only is less than 215 ohms, REPAIR circuits CH204 (GY/OG) and CH233 (VT/BN) for a short together.

If both thehigh-side and low-side resistance is greater than 4,375 ohms, REPAIR circuit CH204 (GY/OG) for an open.

Once the repair is complete, CALIBRATE the actuators. REFER to Calibrating the HVAC Actuators. TEST the system for normal operation.

H5 CHECK THE ACTUATOR FEEDBACK CIRCUIT FOR A SHORT TO VOLTAGE

- Ignition ON.

- Measure the voltage between ground and HVAC module C228A-1, circuit CH204 (GY/OG), harness side.





Is any voltage present?

Yes
REPAIR circuit CH204 (GY/OG) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

No
GO to H6.

H6 CHECK THE ACTUATOR FEEDBACK CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Measure the resistance between ground and HVAC module C228A-1, circuit CH204 (GY/OG), harness side.





Are the resistances greater than 10,000 ohms?

Yes
GO to H7.

No
REPAIR circuit CH204 (GY/OG) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

H7 CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR OPERATION

- Ignition OFF.

- Disconnect: HVAC Module C228A (If not previously disconnected).

- Measure the resistance between HVAC module C228A-2, circuit CH233 (VT/BN), harness side and HVAC module C228A-1, circuit CH204 (GY/OG), harness side.





- Connect a fused jumper wire between:
- HVAC module C228A-10, circuit SBP07 (WH/RD), harness side and HVAC module C228A-7, circuit CH202 (BU/GN), harness side.

- HVAC module C228A-13, circuit GD115 (BK/GY), harness side and HVAC module C228A-8, circuit CH203 (GN/BN), harness side.






- Remove the fused jumpers.

- Connect a fused jumper wire between:
- HVAC module C228A-13, circuit GD115 (BK/GY), harness side and HVAC module C228A-7, circuit CH202 (BU/GN), harness side.

- HVAC module C228A-10, circuit SBP07 (WH/RD), harness side and HVAC module C228A-8, circuit CH203 (GN/BN), harness side.






Does the resistance smoothly increase to approximately 3,500 ohms and/or decrease to approximately 290 ohms when the jumpers are connected?

Yes
GO to H14.

No
GO to H8.

H8 CHECK THE DEFROST/PANEL/FLOOR MODE DOOR AND LINKAGE

- Disconnect: Defrost/Panel/Floor Mode Door Actuator C236.

- REMOVE the defrost/panel/floor mode door actuator.

- INSPECT the defrost/panel/floor mode door and linkage for a broken, loose or binding condition.

Is any condition found during inspection?

Yes
REPAIR the defrost/panel/floor mode door or linkage REINSTALL the defrost/panel/floor mode door actuator. CALIBRATE the actuators. REFER to Calibrating the HVAC Actuators. TEST the system for normal operation.

No
GO to H13.

H9 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO VOLTAGE

- Ignition OFF.

- Disconnect: HVAC Module C228A.

- Ignition ON.

- Measure the voltage between ground and:
- HVAC module C228A-7, circuit CH202 (BU/GN), harness side.

- HVAC module C228A-8, circuit CH203 (GN/BN), harness side.






Are any voltages present?

Yes
REPAIR circuit CH202 (BU/GN) or CH203 (GN/BN) for a short to voltage. TEST the system for normal operation.

No
GO to H10.

H10 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO GROUND

- Ignition OFF.

- Measure the resistance between ground and:
- HVAC module C228A-7, circuit CH202 (BU/GN), harness side.

- HVAC module C228A-8, circuit CH203 (GN/BN), harness side.






Are the resistances greater than 10,000 ohms?

Yes
GO to H11.

No
REPAIR circuit CH202 (BU/GN) or CH203 (GN/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

H11 CHECK THE ACTUATOR MOTOR AND CIRCUIT RESISTANCE

- Measure the resistance between HVAC module C228A-7, circuit CH202 (BU/GN), harness side and HVAC module C228A-8, circuit CH203 (GN/BN), harness side.





Is the resistance greater than 30 ohms?

Yes
GO to H14.

No
GO to H12.

H12 CHECK THE ACTUATOR MOTOR CIRCUITS FOR A SHORT TOGETHER

- Disconnect: Defrost/Panel/Floor Mode Door Actuator C236.

- Measure the resistance between HVAC module C228A-7, circuit CH202 (BU/GN), harness side and HVAC module C228A-8, circuit CH203 (GN/BN), harness side.





Is the resistance greater than 10,000 ohms?

Yes
GO to H13.

No
REPAIR circuits CH202 (BU/GN) and CH203 (GN/BN) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

H13 CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR CONNECTION

- Disconnect the defrost/panel/floor mode door actuator connector.

- Inspect the defrost/panel/floor mode door actuator connector for:
- corrosion.
- pushed-out terminals.
- damaged terminals.


- REINSTALL the defrost/panel/floor mode door actuator, If removed.

- Connect and correctly seat the defrost/panel/floor mode door actuator connector.

- CALIBRATE the actuators. REFER to Calibrating the HVAC Actuators.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new defrost/panel/floor mode door actuator. CALIBRATE the actuators. REFER to Calibrating the HVAC Actuators. 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. TEST the system for normal operation.

H14 CHECK THE HVAC MODULE CONNECTION

- Disconnect all the HVAC module connectors.

- Inspect the HVAC module connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.


- Connect and correctly seat all the HVAC module connectors.

- 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.