Blend/Mode/Recirc Door Operation Improper - Single-Zone

BLEND/MODE/RECIRC DOOR OPERATION IMPROPER (SINGLE-ZONE)

Blend/Mode/Recirc Door Operation Improper (Single-Zone):

POSSIBLE CAUSES
- Door driver circuit(s) shorted to ground
- Door driver circuit(s) shorted to voltage
- Door driver circuit shorted to other door driver circuit(s)
- Door driver circuit(s) open
- Door(s) bound up, warped, worn, damaged
- Door linkage(s) excessively worn, disconnected, missing, broken
- Door actuator(s) broken

Diagnostic Test

1. RUN THE ACTUATOR CIRCUIT TEST

NOTE: Diagnose and repair all Actuator Circuit Test faults before diagnosing Calibration faults.

Turn the ignition on.
With the DRBIII(R) in HVAC, select System Tests and then select Actuator Circuit Test.
Allow the test to run to completion before proceeding.

Q: Does the DRBIII(R) display any Actuator Circuit Test fault messages?

YES: Diagnose and repair the fault(s). Refer to *ACTUATOR CIRCUIT TEST DIAGNOSTICS (SINGLE-ZONE) for the diagnostic test procedure.
NO: Go To 2

2. CHECK FOR DTCS IN THE A/C HEATER CONTROL

NOTE: Diagnose and repair all Overcurrent DTCs before diagnosing Calibration faults.

With the DRBIII(R), read HVAC DTCs.

Q: Does the DRBIII(R) display any DTCs?

YES: Diagnose and repair the DTC(s).
NO: Go To 3

3. RUN THE HVAC DOOR RECALIBRATION TEST

NOTE: Diagnose and repair all Actuator Circuit Test faults and all Overcurrent DTCs before diagnosing Calibration faults.

With the DRBIII(R) in HVAC, select System Tests and then select HVAC Door Recalibration.
Allow the test to run to completion before proceeding.

Q: Does the DRBIII(R) display any HVAC Door Recalibration fault messages?

YES: Diagnose and repair the fault(s).
NO: Go To 4

4. SELECT THE APPLICABLE TEST TO DIAGNOSE THE DOOR WITH THE REPORTED FAULT

Select the applicable test to diagnose the door with the reported fault

Mode Door Function Test
Go To 5

Blend Door Function Test
Go To 6

Recirculation Door Function Test
Go To 7

5. CHECK MODE DOOR 1 & MODE DOOR 2 FUNCTION
Start the engine.
Turn the Blower control to the high speed position.

NOTE:
- The Mode Door 1 must be at its physical end of travel in the panel position to correctly direct airflow to the Mode Door 2.
- The Mode Door 2 must be at its physical end of travel in the floor-defrost position to correctly direct airflow to the Mode Door 1.

Turn the Mode Select control to each door position for a minimum of 30 seconds and check for airflow from the corresponding vents.

Q: Does air flow from the correct vents for each door position?

YES: Test Complete.
NO: Remove the Mode Door Actuator 1 and the Mode Door Actuator 2 from the A/C-Heater Housing Assembly. By hand, one door actuator at a time, attempt to rotate the door actuator in both directions. Also, inspect for disconnected, missing, or broken door actuator linkage, and bound up, warped, worn, and damaged doors. Repair as necessary. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

6. CHECK BLEND DOOR FUNCTION
Start the engine.
Turn the Blower control to the high speed position.
Turn the Mode Select control to the panel position.
Move the Blend control to the full hot position.
Move the Blend control to the full cold position, in 25% increments, while checking for a change in airflow air temperature coming from the panel vents.

Q: Does the airflow air temperature change with respect to the position of the blend control?

YES: Test Complete.
NO: Remove Blend Door Actuator from A/C-Heater Housing Assembly. By hand, attempt to rotate the door actuator in both directions. Also, inspect for disconnected, missing, or broken door actuator linkage, and a bound up, warped, worn, and damaged door. Repair as necessary. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

7. CHECK RECIRCULATION DOOR FUNCTION
Start the engine.
Turn the Blower control to the high speed position.
Press the MAX control off (LED not Illuminated).
Press the MAX control on (LED Illuminated). The sound of the air flowing through the ducts should get louder as the recirculation door opens to bring in recirculated air.

Q: Does the sound of the airflow get louder after pressing the MAX control on?

YES: Test Complete.
NO: Remove Recirculation Door Actuator from A/C-Heater Housing Assembly. By hand, attempt to rotate the door actuator in both directions. Also, inspect for disconnected, missing, or broken door actuator linkage, and a bound up, warped, worn, and damaged door. Repair as necessary. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test