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Home >> Alfa Romeo >> 2019 >> Giulia Base, AWD >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> (Heating & Air Conditioning - Electrical Diagnostics) >> DTC Troubleshooting >> B1901-11 - Distribution Defrost Left Motor Feedback-Circuit Short To Ground >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    1. With the scan tool, read HVAC DTCs and record on the repair order.
    2. Record the Environmental Data.
    3. With the scan tool, erase DTCs.
    4. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    5. With the scan tool, read HVAC DTCs.

      Did the DTC return?

      Yes 

      • Go To  3

      No 

      • Go To  2
  2. PERFORM THE HVAC ACTUATOR CALIBRATION TEST 
    1. With the scan tool, perform the HVAC Actuator Calibration Test.

      Did this DTC change from Stored to Active while performing the HVAC Actuator Calibration Test?

      Yes 

      • Go To  5

      No 

      • Go To  3
  3. CHECK THE (C324) LEFT DEFROST MODE DOOR SIGNAL CIRCUIT FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Disconnect the HVAC Module C1 harness connector.
    3. Disconnect the Left Defrost Mode Door Actuator harness connector.
    4. Check for continuity to ground in the (C324) Left Defrost Mode Door Signal circuit between Pin 2 of the Left Defrost Mode Door Actuator harness connector and Pin 7 of the HVAC Module C1 harness connector.

      Is continuity to ground present in the (C324) Left Defrost Mode Door Signal circuit?

      Yes 

      • Repair the (C324) Left Defrost Mode Door Signal circuit for a short to ground.
      • Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  4
  4. CHECK THE (C807) LEFT DEFROST MODE DOOR DRIVER 2 CIRCUIT FOR A SHORT TO GROUND 
    1. Check for continuity to ground in the (C807) Left Defrost Mode Door Driver 2 circuit between Pin 6 of the Left Defrost Mode Door Actuator harness connector and Pin 38 of the HVAC Module C1 harness connector.

      Is continuity to ground present in the (C807) Left Defrost Mode Door Driver 2 circuit ?

      Yes 

      • Repair the (C807) Left Defrost Mode Door Driver 2 circuit for a short to ground.
      • Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  5
  5. CHECK THE LEFT DEFROST MODE DOOR ACTUATOR FOR PROPER OPERATION 
    1. Replace the Left Defrost Mode Door Actuator in accordance with the Service Information. Refer to ACTUATOR, MODE DOOR, REMOVAL AND INSTALLATION .
    2. With the scan tool, erase HVAC DTCs and perform the HVAC Actuator Calibration Test.

      Did this DTC reset?

      Yes 

      • Go To  6

      No 

  6. CHECK RELATED HARNESS CONNECTIONS 
    1. Disconnect all HVAC Module harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Perform a terminal drag test on each connector terminal to verify proper terminal tension.

      Repair any conditions that are found.

    5. Reconnect all HVAC Module harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. With the scan tool, erase DTCs.
    9. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    10. With the scan tool, read HVAC Module DTCs.

      Did the DTC return?

      Yes 

      No 

      • Repair any faulty connections.
      • Perform the HVAC MODULE VERIFICATION TEST. Refer to STANDARD PROCEDURE .