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DTC B2422: Interior Light Rheostat 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 B2420 is also set, go to next step. If DTC B2420 is not also 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 C2. Using DVOM, measure resistance in Yellow wire between headlight switch connector terminal B3 and IPM connector C2 terminal B8. See WIRING DIAGRAMS  . 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. Using DVOM, measure resistance between ground and IPM connector 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 in Light Blue/Black wire between headlight switch connector terminal No. B1 and IPM connector C2 terminal B12. If resistance is less than 5 ohms, go to step  14 . If resistance is not less than 5 ohms, go to step  18 .
  7. Reconnect IPM connector C2. Turn ignition switch to ON position. Connect scan tool to Data Link Connector (DLC). Select OPEN/SHORT data from IPM data display. Monitor TWILIGHT DELAY POT counts. Set instrument panel dimmer switch to maximum value. If counts for TWILIGHT DELAY POT are greater than 250 counts (4.7 volts), go to step  9 . If counts for TWILIGHT DELAY POT are less than 250 counts (4.7 volts), go to next step.
  8. Set instrument panel dimmer switch to minimum value. If counts for TWILIGHT DELAY POT are less than 17 counts (0.3 volts), go to step  11 . If counts for TWILIGHT DELAY POT are greater than 17 counts (0.3 volts), go to step  14 .
  9. Disconnect headlight switch connector. Using DVOM, measure resistance between headlight switch terminals B2 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 .
  10. Disconnect IPM connector C2. Using DVOM, measure resistance in Dark Green wire between headlight switch connector terminal B2 and IPM connector C2 terminal B11. If resistance is less than 5 ohms, go to step  14 . If resistance is greater than 5 ohms, go to step  19 .
  11. Disconnect headlight switch connector. Using DVOM, measure resistance between headlight switch terminals B2 and B3 (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 C2. Using DVOM, measure resistance between ground and IPM connector C2 terminal B11 (Dark Green wire). If resistance is less than 5 ohms, go to step  20 . If resistance is greater 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 B2422 resets, go to next step. If DTC B2422 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 Dark Green wire between IPM and headlight switch. After repairs, go to step  21 .
  20. Repair short to ground in Dark Green 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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