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Home >> Suzuki >> 2009 >> XL7 Limited, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Headlights >> Lighting Systems >> Diagnostic Information and Procedures >> DTC B257A: Headlamp Switch Input Signals Mismatch >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
  2. Ignition ON, test for B+ between the signal circuit terminals listed below and ground.
    • Headlamp switch headlamps ON signal terminal 2
    • Park lamp switch ON signal terminal 3
    • Headlamp switch OFF signal terminal 4
    • If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  3. Connect a 3A fused jumper wire between the headlamp OFF signal circuit terminal 4 and ground. Verify the scan tool Auto Hdlp. Disable Sw. parameter is Active.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Connect a 3A fused jumper wire between the park lamp ON signal circuit terminal 3 and ground. Verify the scan tool Parklamp Switch parameter is Active.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Connect a 3A fused jumper wire between the headlamps ON signal circuit terminal 2 and ground. Verify the scan tool Headlamp Switch parameter is Active.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal replace the BCM.
  6. If all circuits test normal, replace the turn signal/multifunction switch.
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