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Home >> Cadillac >> 1998 >> Seville STS >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Body Control Module >> Diagnosis & Testing >> DTC B2419: Twilight Photocell Circuit Problem >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform BCM diagnostic system check. See BCM DIAGNOSTIC SYSTEM CHECK  . After performing system check, go to next step.
  2. Turn ignition on. Using scan tool, select OPEN/SHORT DATA from IPM DATA DISPLAY. Set twilight photocell units to COUNTS. Cover ambient light sensor. If scan tool indicates that twilight photocell value is greater than 250 counts, go to step 5). If scan tool does not indicate that twilight photocell value is greater than 250 counts, go to next step.
  3. Expose sensor to bright incandescent light. If twilight photocell value is now less than 5 counts, go to step 8). If twilight photocell value is not less than 5 counts, go to next step.
  4. Replace IPM. After replacing IPM, go to step 12).
  5. Turn ignition off. Disconnect ambient light sensor connector. Using DVOM, check resistance between sensor terminals "A" and "B". See WIRING DIAGRAMS  . If resistance is greater than 31,000 ohms, go to step 10). If resistance is not greater than 31,000 ohms, go to next step.
  6. Disconnect IPM harness connector C2. Check resistance between IPM harness connector terminal B5 (White wire) and ambient light sensor connector terminal "A" (White wire). See WIRING DIAGRAMS  . If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, go to step 11).
  7. Repair open in Yellow wire between splice and ambient light sensor. After repairs, go to step 12).
  8. Turn ignition off. Disconnect ambient light sensor connector. Using DVOM, check resistance between sensor terminals "A" and "B". If resistance is greater than 23,000 ohms, go to step 10). If resistance is not greater than 23,000 ohms, go to next step.
  9. Repair short to ground in White wire. After repairs, go to step 12).
  10. Replace ambient light sensor. After replacing ambient light sensor, go to step 12).
  11. Repair open on White wire between IPM and ambient light sensor. After repairs, go to next step.
  12. Turn ignition off. Reconnect components and connectors. Clear DTCs. After clearing DTCs, perform BCM diagnostic check. See procedures in BCM DIAGNOSTIC SYSTEM CHECK  .
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