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Home >> Saab >> 2010 >> 9-5 >> Repair and Diagnosis >> Electrical >> Horns >> Lighting And Signaling Systems >> Fault diagnosis, fault codes >> DTC B3410: Automatic Headlamp Leveling Control Module Front Axle Sensor Signal Circuit or B3420: Automatic Headlamp Leveling Control Module Rear Axle Sensor Signal Circuit >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate headlamp leveling sensor.
  2. Disconnect the negative terminal of the C1 Battery.
  3. Test for less than 5 Ω between the low reference circuit terminal 1 and ground.
  4. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K26 Headlamp Control Module.
  5. Reconnect the negative terminal to the C1 Battery.
  6. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground.
  7. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K26 Headlamp Control Module.
  8. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K26 Headlamp Control Module.
  9. Test for 4.8-5.2 V between the signal circuit terminal 2 and ground.
  10. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K26 Headlamp Control Module.
  11. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K26 Headlamp Control Module.
  12. Ignition OFF, connect the harness connector to the appropriate headlamp leveling sensor.
  13. Ignition ON, automatic light ON.
  14. Move a piece of sheet metal in the air gap between the appropriate headlamp leveling sensor and the sensor metal plate. The value of the scan tool leveling sensor parameter listed below should vary:
    • Front Levelling Position Sensor
    • Rear Levelling Position Sensor
  15. If the appropriate value does not change, replace the appropriate headlamp leveling sensor.
  16. Move a piece of sheet metal in the air gap between the appropriate headlamp leveling sensor and the sensor metal plate. The headlamps low beam should move up or down.
  17. If the headlamps low beam does not move up or down, replace the K26 Headlamp Control Module.
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