2000 Cadillac Seville SLSFACTORY OEM SERVICE PROCEDURE

DTC B1805: Ignition Switch Problem: Testing

  1. If body control system diagnostic system check has been performed, go to next step. If body control system diagnostic system check has not been performed, go to BODY CONTROL SYSTEM DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Connect scan tool to Data Link Connector. See Figure . Turn ignition off. Using scan tool, select DASH INTEGRATION MODULE data list. Monitor IGNITION SWITCH parameters. If all IGNITION SWITCH parameters display INACTIVE, go to next step. If all IGNITION SWITCH parameters do not display INACTIVE, go to step  7 .
  3. Turn ignition on. With the scan tool observe the ignition switch parameters. Monitor IGNITION SWITCH parameters. If all IGNITION SWITCH parameters display ACTIVE, go to next step. If all IGNITION SWITCH parameters do not display ACTIVE, go to step  9 .
  4. Turn ignition to CRANK position. Monitor IGNITION SWITCH parameters. If only RUN/CRANK and IGN. UNLOCK parameters display ACTIVE, go to next step. If only RUN/CRANK and IGN. UNLOCK parameters do not display ACTIVE, go to step  7 .
  5. Turn ignition to UNLOCK position. If only IGN. UNLOCK parameter displays ACTIVE, go to next step. If only IGN. UNLOCK parameter does not display ACTIVE, go to step  7 .
  6. Turn ignition to ACCY. position. If only IGN. ACCESSORY parameter does not display ACTIVE, go to next step. If only IGN. ACCESSORY parameter displays ACTIVE, go to step  11 .
  7. Turn ignition off. Remove radio for access and disconnect ignition switch connectors. See Fig 1 . See RADIO  under REMOVAL & INSTALLATION. Monitor IGNITION SWITCH parameters. If previously ACTIVE parameters do not change to INACTIVE, go to next step. If previously ACTIVE parameters change to INACTIVE, go to step  10 .
  8. Check for short to voltage in Pink, Brown, Orange, Yellow or White wires between ignition switch connectors and DIM connector C2. See WIRING DIAGRAMS  . If circuits are okay, go to step  11 . If faulty circuit is found and repaired, go to step  14 .
  9. Check for open or high resistance in Pink, Brown, Orange, Yellow or White wires between ignition switch connectors and DIM connector C2. See WIRING DIAGRAMS  . If circuits are okay, go to step  11 . If faulty circuit is found and repaired, go to step  14 .
  10. Check for poor connections at ignition switch connector. If connections are okay, go to step  12 . If faulty connections are found and repaired, go to step  14 .
  11. Check for poor connections at DIM connector. If connections are okay, go to step  13 . If faulty connections are found and repaired, go to step  14 .
  12. Replace ignition switch. See IGNITION SWITCH under REMOVAL & INSTALLATION in ANALOG INSTRUMENT PANELS - SEVILLE article. After repairs, go to step  14 .
  13. Replace DIM. See DASH INTEGRATION MODULE (DIM)  under REMOVAL & INSTALLATION. After repairs, go to next step.
  14. Use scan tool to clear DTCs. Recheck system operation for module that set DTC. Recheck for DTC. If DTC B1805 resets, go to step  2 . If DTC does not reset, repair is complete.
Fig 1: Locating Ignition Switch & Connectors (View Through Radio Opening)
G98F12448Courtesy of GENERAL MOTORS CORP.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.