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Diagnostic Test

WARNING: This page is about a different car, the 2006 Dodge Magnum, 2006 Dodge Charger, and 2006 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. 1)  INSPECT THE A/C HEATER CONTROL FOR DAMAGE 

    Turn the ignition off.

    Inspect the A/C Heater Control for damage.

    Is the A/C Heater Control damaged? 

    Yes 

    1. Replace the A/C Heater Control in accordance with the Service Information.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .

    No 

    1. Go To step  2).
  2. 2)  INSPECT FOR OBJECT OR SUBSTANCE CAUSING THE A/C MODE SWITCH TO STAY OR STICK IN A PUSHED POSITION 

    Inspect the A/C Heater Control for anything that would cause the A/C mode switch to stay or stick in a pushed position.

    Is anything present that would cause the A/C mode switch to stay or stick in a pushed position? 

    Yes 

    1. Repair as necessary.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .

    No 

    1. Go To step  3).
  3. 3)  CHECK THE (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT VOLTAGE 
    Fig 1: Measuring Voltage Of Blower Switch Position Signal Circuit
    GC0039701Courtesy of DAIMLERCHRYSLER CORP.

    Disconnect the A/C Heater Control C3 harness connector.

    Turn the ignition on.

    Measure the voltage of the (C850) Blower Switch Position Signal circuit.

    What is the voltage? 

    Below 4.8 Volts 

    1. Go To step  4).

    Above 5.2 Volts 

    1. Go To step  8).

    4.8 Volts To 5.2 Volts 

    1. Go To step  9).
  4. 4)  CHECK THE (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT FOR A SHORT TO THE (Z908) GROUND CIRCUIT 
    Fig 2: Checking Blower Switch Position Signal Circuit For Short To Ground
    GC0039702Courtesy of DAIMLERCHRYSLER CORP.

    Turn the ignition off.

    Measure the resistance between the (C850) Blower Switch Position Signal circuit and the (Z908) Ground circuit in the A/C Heater Control C3 harness connector.

    Is the resistance below 10K ohms? 

    Yes 

    1. Repair the (C850) Blower Switch Position Signal circuit for a short to the (Z908) Ground circuit.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .

    No 

    1. Go To step  5).
  5. 5)  CHECK THE (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT FOR A SHORT TO THE (Z909) GROUND CIRCUIT 
    Fig 3: Measuring Resistance Between Blower Switch Position Signal & Ground Circuits
    GC0039703Courtesy of DAIMLERCHRYSLER CORP.

    Disconnect the A/C Heater Control C1 harness connector.

    Measure the resistance between the (C850) Blower Switch Position Signal circuit and the (Z909) Ground circuit in the A/C Heater Control C1 harness connector.

    Is the resistance below 10K ohms? 

    Yes 

    1. Repair the (C850) Blower Switch Position Signal circuit for a short to the (Z909) Ground circuit.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .

    No 

    1. Go To step  6).
  6. 6)  CHECK THE (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT FOR A SHORT TO GROUND 
    Fig 4: Checking Blower Switch Position Signal Circuit For Short To Ground
    GC0039704Courtesy of DAIMLERCHRYSLER CORP.

    Measure the resistance of the (C850) Blower Switch Position Signal circuit between ground and the A/C Heater Control C3 harness connector.

    Is the resistance below 10K ohms? 

    Yes 

    1. Repair the (C850) Blower Switch Position Signal circuit for a short to ground.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .

    No 

    1. Go To step  7).
  7. 7)  CHECK (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT FOR AN OPEN 
    Fig 5: Checking Blower Switch Position Signal Circuit For An Open
    GC0039705Courtesy of DAIMLERCHRYSLER CORP.

    Measure the resistance of the (C850) Blower Switch Position Signal circuit between the A/C Heater Control C1 harness connector and the A/C Heater Control C3 harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Replace the A/C Heater Control in accordance with the Service Information.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .

    No 

    1. Repair the (C850) Blower Switch Position Signal circuit for an open.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
  8. 8)  CHECK THE (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE 
    Fig 6: Measuring Voltage Of Blower Switch Position Signal Circuit
    GC0039701Courtesy of DAIMLERCHRYSLER CORP.

    Turn the ignition off.

    Disconnect the A/C Heater Control C1 harness connector.

    Turn the ignition on.

    Measure the voltage of the (C850) Blower Switch Position Signal circuit at the A/C Heater Control C3 harness connector.

    Is the voltage above 0.2 volts? 

    Yes 

    1. Repair the (C850) Blower Switch Position Signal circuit for a short to voltage.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .

    No 

    1. Replace the A/C Heater Control in accordance with the Service Information.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
  9. 9)  CHECK FOR NORMAL A/C MODE SWITCH & STATUS INDICATOR FUNCTION 

    Turn the ignition off.

    Reconnect the A/C Heater Control C3 harness connector.

    Turn the ignition on.

    Turn the Blower control on.

    Press the A/C mode switch on and off several times while observing the A/C status indicator.

    Does the A/C status indicator turn on and off with respect to the switch position? 

    Yes 

    1. Go To step  10).

    No 

    1. Replace the A/C Heater Control in accordance with the Service Information.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
  10. 10)  CHECK A/C HEATER CONTROL OPERATION BY ATTEMPTING TO ENTER DIAGNOSTIC MODE 

    If illuminated, turn off the A/C status indicator and the EBL status indicator.

    Actuate the display DTC function by performing the following:

    • Turn the blower control on.
    • Press the A/C mode switch down, turn the blower control to off, wait until both LEDs illuminate (approximately 5 seconds) and then release the A/C mode switch.

    When entry mode is recognized, the A/C status indicator and the EBL status indicator will illuminate for 5 seconds and then display DTCs, if present. The A/C status indicator displays active DTCs when the EBL status indictor is not illuminated and stored DTCs when the EBL status indicator is illuminated. However, if no DTCs are present, both status indicators will turn off and the system will exit diagnostic mode.

    Did the A/C Heater Control enter diagnostic mode? 

    Yes 

    1. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .

    No 

    1. Replace the A/C Heater Control in accordance with the Service Information.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
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