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Test Al: Turn Signal Lights &/Or Indicators Inoperative

  1. If lighting system diagnostic system check has been performed, go to next step. If light system diagnostic system check has not been performed, perform lighting system diagnostic system check. See LIGHTING SYSTEM DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Place turn signal switch in right side ON position, then left side ON position. If turn signals operate properly, go to DIAGNOSING INTERMITTENTS  . If turn signals do not operate properly, go to next step.
  3. If all turn signals and indicators operate, go to next step. If all turn signals and indicators are inoperative, go to step  5 .
  4. If only turn signals are inoperative, go to step  9 . If only turn signal indicators are inoperative, go to step  20 .
  5. Check TURN SIGNALS CORN LPS fuse in instrument panel fuse block for an open. See Figure . If fuse is okay, go to next step. If fuse is blown, go to step  27 .
    6. NOTE: Turn signal/hazard flasher module may also be referred to as hazard and turn signal flasher.
    Fig 1: Identifying Turn Signal/Hazard Flasher Module Harness Connector Terminals
    G00032228Courtesy of GENERAL MOTORS CORP.
  6. Turn ignition switch to RUN position. Remove turn signal/hazard flasher module. Turn signal/hazard flasher module is located behind left side of instrument panel. Connect a test light between ground and turn signal/hazard flasher module harness connector terminal A1 (Light Blue wire). See Fig 1 . If test light illuminates, go to next step. If test light does not illuminate, go to step  18 .
  7. Connect test light between turn signal/hazard flasher module harness connector terminals A1 (Light Green wire) and B2 (Black wire). If test light illuminates, go to next step. If test light does not illuminate, go to step  25 .
  8. Install a fused jumper wire between turn signal/hazard flasher module harness connector terminals A1 (Light Green wire) and C1 (Purple wire). Place turn signal switch in right side ON position, then left side ON position. If turn signals do not illuminate, go to step  17 . If turn signals illuminate, go to step  21 .
  9. If front turn signals are inoperative, go to next step. If rear turn signals are inoperative, go to step  14 .
  10. Turn ignition switch to RUN position. Disconnect inoperative front turn signal harness connector. Connect a test light between ground and turn signal harness connector Light Blue wire terminal (left side) or Dark Blue wire terminal (right side). Place turn signal switch in appropriate ON position. If test light does not flash on and off, go to next step. If test light flashes on and off, go to step  15 .
  11. Turn ignition switch to OFF position. Disconnect Body control Module (BCM) Blue harness connector C1. BCM is located behind left side of instrument panel, to left of steering column. See Figure . Connect a test light between ground and BCM harness connector C1 terminal "E" (Light Blue wire) for left front turn signal and/or terminal "F" (Dark Blue wire) for right front turn signal. See Figure . Place turn signal switch in appropriate ON position. If test light does not flash on and off, go to next step. If test light flashes on and off, go to step  13 .
  12. Test Dark Blue wire between Instrument Panel Cluster (IPC) harness connector terminal A11 and BCM harness connector C1 terminal "H" (right front turn signal) and/or Light Blue wire between IPC harness connector terminal A10 and BCM Blue harness connector C1 terminal "G" (left front turn signal) for an open or high resistance. See Figure and Figure . If an open or high resistance is not found, go to step  22 . If an open or high resistance is found, repair as necessary. After repair, go to step  36 .
  13. Test Dark Blue wire between right front turn signal harness connector and BCM harness connector C1 terminal "F" and/or Light Blue wire between left front turn signal harness connector and BCM harness connector C1 terminal "E" for an open or high resistance. If an open or high resistance is not found, go to step  35 . If an open or high resistance is found, repair as necessary. After repair, go to step  36 .
  14. Turn ignition switch to RUN position. Disconnect inoperative rear turn signal harness connector. Connect a test light between ground and turn signal harness connector Yellow wire terminal (left side) or Dark Green wire terminal (right side). Place turn signal switch in appropriate ON position. If test light flashes on and off, go to next step. If test light does not flash on and off, go to step  16 .
  15. Connect a test light across inoperative turn signal harness connector. Place turn signal switch in appropriate ON position. If test light illuminates, go to step  24 . If test light does not illuminate, go to step  28 .
  16. Test Dark Green wire between right rear turn signal harness connector and multifunction switch harness connector and/or Yellow wire between left rear turn signal harness connector and multifunction switch harness connector for an open or high resistance. See WIRING DIAGRAMS  . If an open or high resistance is not found, go to step  22 . If an open or high resistance is found, repair as necessary. After repair, go to step  36 .
  17. Test Purple wire between multifunction switch harness connector and turn signal/hazard flasher module harness connector for an open or high resistance. See Fig 1 . If an open or high resistance is not found, go to step  22 . If an open or high resistance is found, repair as necessary. After repair, go to step  36 .
  18. Using test light connected to ground, backprobe Black 48-pin in-line connector C201 terminal E12 (White wire). See Fig 2 . If test light illuminates, go to next step. If test light does not illuminate, go to step  29 .
    Fig 2: Identifying In-Line Connector C201 Terminals
    G00032229Courtesy of GENERAL MOTORS CORP.
    19. NOTE: Light Blue wire at in-line connector C201 male side, changes to Orange wire at in-line connector C201 female side.
  19. Using test light connected to ground, backprobe in-line connector C201 terminal E6 (Light Blue wire). If test light does not illuminate, go to step  22 . If test light illuminates, go to step  30 .
  20. Turn ignition switch to OFF position. Disconnect Instrument Panel Cluster (IPC) harness connector. Connect a test light between IPC harness connector terminals A1 (Black wire) and A10 (Light Blue wire) for left turn signal indicator or A11 (Dark Blue wire) for right turn signal indicator. See Figure . Place turn signal switch in appropriate ON position. If test light illuminates, go to step  23 . If test light does not illuminate, go to step  26 .
  21. Check for poor connections at turn signal/hazard flasher module harness connector. If poor connections are not found, go to step  32 . If poor connections are found, repair as necessary. After repair, go to step  36 .
  22. Check for poor connections at multifunction switch harness connector. If poor connections are not found, go to step  31 . If poor connections are found, repair as necessary. After repair, go to step  36 .
  23. Check for poor connections at IPC harness connector. If poor connections are not found, go to step  33 . If poor connections are found, repair as necessary. After repair, go to step  36 .
  24. Check for poor connections at inoperative turn signal harness connector. If poor connections are not found, go to step  34 . If poor connections are found, repair as necessary. After repair, go to step  36 .
  25. Repair open or high resistance in Black wire between signal/hazard flasher module harness connector and ground point G201. Ground point G201 is located below instrument panel, to left of steering column. After repair, go to step  36 .
  26. Repair open or high resistance in Light Blue wire for left turn signal indicator or Dark Blue wire for right turn signal indicator between IPC harness connector and BCM. After repair, go to step  36 .
    27. NOTE: Turn signal/hazard flasher module may also be referred to as hazard and turn signal flasher.
  27. Repair short to ground in Pink wire between instrument panel fuse block and multifunction switch or Purple wire between turn signal/hazard flasher module and multifunction switch. See WIRING DIAGRAMS  . After repair, go to step  36 .
  28. Repair open or high resistance in Black wire between inoperative front turn signal harness connector ground point G101. Ground point G101 is located on front left side of radiator support. After repair, go to step  36 .
  29. Repair open or high resistance in White wire between in-line connector C201 and multifunction switch. After repair, go to step  36 .
    30. NOTE: Light Blue wire at in-line connector C201 male side, changes to Orange wire at in-line connector C201 female side.
  30. Repair open or high resistance in Orange wire between in-line connector C201 and multifunction switch. After repair, go to step  36 .
    31. NOTE: Turn signal switch is integral part of multifunction switch.
  31. Replace turn signal switch. See appropriate STEERING COLUMN SWITCHES article. After repair, go to step  36 .
    32. NOTE: Turn signal/hazard flasher module may also be referred to as hazard and turn signal flasher.
  32. Replace turn signal/hazard flasher module. See TURN SIGNAL/HAZARD FLASHER MODULE  under REMOVAL & INSTALLATION. After repair, go to step  36 .
  33. Replace IPC. See INSTRUMENT PANEL CLUSTER  under REMOVAL & INSTALLATION. After repair, go to step  36 .
  34. Replace inoperative turn signal bulb. After repair, go to step  36 .
  35. Replace BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. After repair, go to next step.
  36. Operate system to verify repair. If system does not operate properly, go to step  2 . If system operates properly, system is okay.
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