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DTC B2420: Twilight Delay Pot Failure: Testing

  1. If body control system diagnostic check has been performed, go to next step. If body control system diagnostic check has not been performed, perform body control system diagnostic check. See BODY CONTROL SYSTEM DIAGNOSTIC CHECK  under SYSTEM TESTS.
  2. If DTC B2422 is set, go to next step. If DTC B2422 is not set, go to step  7 .
  3. Disconnect headlight switch connector. Using DVOM, measure resistance between headlight switch terminals B1 and B3 (component side). If reading is less than 40 k/ohms, go to next step. If reading is greater than 40 k/ohms, go to step  13 .
  4. Disconnect IPM connector C1. Using DVOM, measure resistance in Yellow wire between headlight switch connector terminal B3 and IPM connector C1 terminal B8. See Figure . If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, go to step  16 .
  5. Disconnect IPM connector C2. measure resistance between ground and IPM connector C2 terminal B12 (Light Blue/Black wire). If resistance is less than 5 ohms, go to step  17 . If resistance is not less than 5 ohms, go to next step.
  6. Using DVOM, measure resistance between headlight switch connector terminal B1 (Light Blue/Black wire) and IPM connector terminal B12 (Light Blue/Black wire). If resistance is less than 5 ohms, go to step  14 . If resistance is not less than 5 ohms, go to step  18 .
  7. Turn ignition switch to ON position. Connect scan tool to Data Link Connector (DLC). Select IPM OPEN/SHORT data display. Monitor TWILIGHT DELAY POT counts. Set twilight delay switch to maximum. If counts for TWILIGHT DELAY POT are greater than 250, go to step  9 . If counts for TWILIGHT DELAY POT are less than 250, go to next step.
  8. Set twilight delay switch to minimum. If counts for TWILIGHT DELAY POT are less than 5, go to step  11 . If counts for TWILIGHT DELAY POT are greater than 5, go to step  14 .
  9. Disconnect headlight switch connector. Using DVOM, measure resistance between headlight switch terminals B3 and B5 (component side). If reading is less than 40 k/ohms, go to next step. If reading is greater than 40 k/ohms, go to step  13 .
  10. Disconnect IPM connector C1. Using DVOM, measure resistance in Purple wire between headlight switch connector terminal B5 and IPM connector C1 terminal D8. If resistance is less than 5 ohms, go to step  14 . If resistance is not less than 5 ohms, go to step  19 .
  11. Disconnect headlight switch connector. Using DVOM, measure resistance between headlight switch terminals B3 and B5 (component side). If reading is less than 5 ohms, go to next step. If reading is greater than 5 ohms, go to step  13 .
  12. Disconnect IPM connector C1. Using DVOM, measure resistance in Purple wire between ground and IPM connector C1 terminal D8. If resistance is less than 5 ohms, go to step  20 . If resistance is not less than 5 ohms, go to step  14 .
  13. Replace headlight switch. After replacing switch, go to step  21 .
  14. Use scan tool to clear DTCs. Turn ignition switch to OFF position, then back to ON position. Recheck for DTCs. If DTC B2420 resets, go to next step. If DTC B2420 does not reset, check for intermittent connection.
  15. Replace IPM. See INSTRUMENT PANEL INTEGRATION MODULE (IPM)  under REMOVAL & INSTALLATION. After replacing IPM, go to step  21 .
  16. Repair open in Yellow wire between headlight switch and IPM. After repairs, go to step  21 .
  17. Repair short to ground in Light Blue/Black wire between IPM and headlight switch. After repairs, go to step  21 .
  18. Repair open in Light Blue/Black wire between IPM and headlight switch. After repairs, go to step  21 .
  19. Repair open in Purple wire between IPM and headlight switch. After repairs, go to step  21 .
  20. Repair short to ground in Purple wire between IPM and headlight switch. After repairs, go to next step.
  21. Reconnect all components and connectors. Turn ignition switch to ON position. Using scan tool, clear DTCs. After clearing DTCs, perform body control system diagnostic check. See BODY CONTROL SYSTEM DIAGNOSTIC CHECK  under SYSTEM TESTS.
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