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Home >> Jeep >> 2007 >> Liberty Limited, RWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Headlights >> Lighting Systems - Exterior - Electrical Diagnostics >> Lamps/Lighting - Exterior >> DTC Troubleshooting >> Headlamp Switch Input Circuit Low >> Diagnostic Test

Diagnostic Test

  1. 1) INTERMITTENT CONDITION 

    Turn the ignition on.

    With the Scan Tool, clear all BCM DTC's.

    Turn the headlamps to the ON position.

    With the Scan Tool, read DTCs.

    Does the Scan Tool display: HEADLAMP SWITCH INPUT CKT LOW? 

    Yes 

    1. Go to step  2).

    No 

    1. The condition is not present at this time. Monitor Scan Tool parameters while wiggling the related wire harness. Refer to any Technical Service Bulletins that may apply. Visually inspect the related wiring harness and connector terminals.
    2. Perform BODY VERIFICATION TEST .
  2. 2) HEADLAMP SWITCH SHORTED 

    Turn the ignition off.

    Disconnect the Multifunction Switch harness connector.

    Turn the ignition on.

    With the Scan Tool, select Body, Body Control Module and read: Headlamp Switch voltage.

    Does the Scan Tool display Headlamp Switch voltage above 4.8 volts? 

    Yes 

    +

    1. Replace the Multifunction Switch.
    2. Perform BODY VERIFICATION TEST .

    No 

    1. Go to step  3).
  3. 3) HEADLAMP SWITCH MUX CIRCUIT SHORT TO MUX RETURN CIRCUIT 
    Fig 1: Identifying Headlamp Switch Return Circuit And MUX Circuit At Multifunction Switch C1 Harness Connector
    GC0046023Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the Body Control Module harness connector.

    Disconnect the Multifunction Switch harness connector.

    Measure resistance between the Headlamp Switch Return circuit and the Headlamp Switch MUX circuit.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Repair the Headlamp Switch MUX circuit for a short to the Headlamp Switch Return circuit.
    2. Perform BODY VERIFICATION TEST .

    No 

    1. Go to step  4).
  4. 4) HEADLAMP SWITCH MUX CIRCUIT SHORT TO GROUND 
    Fig 2: Measuring Resistance Of Headlamp Switch MUX Circuit
    GC0046024Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the Body Control Module harness connector.

    Disconnect the Multifunction Switch harness connector.

    Measure resistance between ground and the Headlamp Switch MUX circuit.

    Is the resistance above 5.0 ohms? 

    Yes 

    1. Repair the Headlamp Switch MUX Circuit for a short to ground condition.
    2. Perform BODY VERIFICATION TEST .

    No 

    1. Go to step  5).
  5. 5) HEADLAMP SWITCH RETURN CIRCUIT SHORT TO GROUND 
    Fig 3: Measuring Resistance Of Headlamp Switch Return Circuit
    GC0046025Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the Body Control Module harness connector.

    Disconnect the Multifunction Switch harness connector.

    Measure resistance between ground and the Headlamp Switch Return circuit.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Repair the Headlamp Switch Return Circuit for a short to ground condition.
    2. Perform BODY VERIFICATION TEST .

    No 

    1. Replace the Body Control Module.
    2. Perform BODY VERIFICATION TEST .