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Home >> Chrysler >> 2009 >> 300 Signature Series >> Repair and Diagnosis >> External Pages >> Different car >> Section 205 ((HVAC Systems - Electrical Diagnostics)) >> 24 - HVAC - Electrical Diagnostics >> DTC Troubleshooting >> B1001-A/C Switch Request Input Circuit Low (CCN) >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2007 Chrysler PT Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
  1. 1) VERIFY DTC B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW IS ACTIVE 

    Turn the ignition on.

    With the scan tool, erase CCN DTCs.

    Turn the ignition off, wait 10 seconds and turn the ignition on.

    With the scan tool, read CCN DTCs.

    Does the scan tool display active: B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW? 

    Yes 

    1. Go to  2).

    No 

    1. Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded or contaminated terminals. Repair as necessary.
    2. Perform BODY VERIFICATION TEST - VER 1 .
  2. 2) CHECK FOR B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW WITH A/C HEATER CONTROL C1 HARNESS CONNECTOR DISCONNECTED 
    Fig 1: A/C Heater Control C1 Harness Connector
    GC0043276Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the A/C Heater Control C1 harness connector.

    Turn the ignition on.

    With the scan tool, erase CCN DTCs.

    Turn the ignition off, wait 10 seconds and turn the ignition on.

    With the scan tool, read CCN DTCs.

    Does the scan tool display: B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW? 

    Yes 

    1. Go to  3).

    No 

    1. Replace the A/C Heater Control in accordance with the Service Information.
    2. Perform BODY VERIFICATION TEST - VER 1 .
  3. 3) CHECK THE (C105) HVAC MUX CONTROL CIRCUIT FOR A SHORT TO GROUND 
    Fig 2: Measuring Resistance Of HVAC MUX Control Circuit
    GC0043277Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the Instrument Cluster C4 harness connector.

    Measure the resistance of the (C105) HVAC MUX Control circuit between ground and the A/C Heater Control C1 harness connector.

    Is the resistance below 10k ohms? 

    Yes 

    1. Repair the (C105) HVAC MUX Control circuit for a short to ground.
    2. Perform BODY VERIFICATION TEST - VER 1 .

    No 

    1. Go to  4).
  4. 4) CHECK THE (C105) HVAC MUX CONTROL CIRCUIT FOR A SHORT TO THE (Z906) GROUND CIRCUIT & THE (C955) HVAC MUX RETURN CIRCUIT 
    Fig 3: Measuring Resistance Between HVAC MUX Control Circuit And HVAC MUX Return Circuit
    GC0043278Courtesy of CHRYSLER LLC

    Measure the resistance between the (C105) HVAC MUX Control circuit and the (Z906) Ground circuit in the A/C Heater Control C1 harness connector.

    Measure the resistance between the (C105) HVAC MUX Control circuit and the (C955) HVAC MUX Return circuit in the A/C Heater Control C1 harness connector.

    Is the resistance below 10k ohms on either circuit? 

    Yes 

    1. Repair all circuits with a resistance below 10k ohms for a short to the (C105) HVAC MUX Control circuit.
    2. Perform BODY VERIFICATION TEST - VER 1 .

    No 

    1. Replace the Instrument Cluster (CCN) in accordance with the Service Information.
    2. Perform BODY VERIFICATION TEST - VER 1 .
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