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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)  CHECK THE BLOWER SPEED SETTING 

    Was the blower control set to high speed before executing the Cooldown Test? 

    Yes 

    1. Go To step  2).

    No 

    1. Start the engine, set the blower control to high speed, and then run the Cooldown Test again.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
  2. 2)  CHECK THE (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT FOR A SHORT TO THE (Z908) GROUND CIRCUIT 
    Fig 1: Checking Blower Switch Position Signal Circuit For Short To Ground
    GC0039702Courtesy of DAIMLERCHRYSLER CORP.

    Turn the ignition off.

    Disconnect the A/C Heater Control C3 harness connector.

    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. Run the Cooldown Test again after the repair is complete.
    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 FOR A SHORT TO THE (Z909) GROUND CIRCUIT 
    Fig 2: 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. Run the Cooldown Test again after the repair is complete.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .

    No 

    1. Go To step  4).
  4. 4)  CHECK THE (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT VOLTAGE 
    Fig 3: Measuring Voltage Of Blower Switch Position Signal Circuit
    GC0039701Courtesy of DAIMLERCHRYSLER CORP.

    Reconnect the A/C Heater Control C1 harness connector.

    Turn the ignition on.

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

    Is the voltage above 4.8 volts? 

    Yes 

    1. Check the blower motor and related circuits for the cause of blower operation problems and repair as necessary. Run the Cooldown Test again after the repair is complete.
    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 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. Run the Cooldown Test again after the repair is complete.
    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 (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. Run the Cooldown Test again after the repair is complete.
    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. Run the Cooldown Test again after the repair is complete.
    2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
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