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Home › Buick › 2001 › LeSabre Custom, 4T65E/MN3 › Repair and Diagnosis › Accessories & Equipment › Cruise Control Systems › System Tests › Test A: Cruise Control Inoperative/Malfunctioning

Test A: Cruise Control Inoperative/Malfunctioning

NOTE: To avoid misdiagnosis, ensure preliminary inspection and all checks have been performed. See TROUBLE SHOOTING  . Ensure proper operation of brakelight system.
  1. If cruise control system diagnostic system check has been performed, go to next step. If cruise control system diagnostic system check has not been performed, go to CRUISE CONTROL SYSTEM DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Turn ignition switch to OFF position. Disconnect cruise control module harness connector. Turn ignition switch to RUN position. Connect a test light between ground and cruise control module harness connector terminal "F" (Pink wire). See Fig 1 . If test light illuminates, go to next step. If test light does not illuminate, go to step  36 .
  3. Connect a test light between cruise control module harness connector terminals "E" (Black wire) and "F" (Pink wire). If test light illuminates, go to next step. If test light does not illuminate, go to step  37 .
  4. Turn cruise control switch off. Using a test light connected to chassis ground, individually probe cruise control harness connector terminals "A" (Gray wire), "B" (Dark Blue wire) and "C" (Gray/Black wire). If test light does not illuminate, go to next step. If test light illuminates at any terminal, go to step  16 .
  5. Turn cruise control switch on. Using a test light connected to chassis ground, probe cruise control harness connector terminal "A" (Gray wire). If test light illuminates, go to next step. If test light does not illuminate, go to step  17 .
  6. Using a test light connected to chassis ground, probe cruise control module harness connector terminal "B" (Dark Blue wire). Press and hold SET/COAST switch. If test light illuminates, go to next step. If test light does not illuminate, go to step  19 .
  7. Using a test light connected to chassis ground, probe cruise control module harness connector terminal "C" (Gray/Black wire). See Fig 1 . Press and hold RESUME/ACCEL switch. If test light illuminates, go to next step. If test light does not illuminate, go to step  20 .
  8. Using a test light connected to chassis ground, probe cruise control module harness connector terminal "D" (Purple wire). If test light illuminates, go to next step. If test light does not illuminate, go to step  21 .
  9. While monitoring test light at Purple wire (terminal "D"), depress brake pedal. If test light does not illuminate, go to next step. If test light illuminates, go to step  22 .
  10. Using a test light, probe cruise control module harness connector terminal "G" (White wire). If test light does not illuminate, go to next step. If test light illuminates, go to step  23 .
  11. While monitoring test light at White wire (terminal "G"), depress brake pedal. If test light illuminates, go to next step. If test light does not illuminate, go to step  24 .
  12. Using a test light connected to battery voltage, probe cruise control module harness connector terminal "H" (Dark Green wire). See Fig 1 . If test light does not illuminate, go to next step. If test light illuminates, go to step  25 .
  13. With test light connected to Dark Green wire (terminal "H"), connect scan tool to Data Link Connector (DLC). DLC is located on lower left side of instrument panel, near steering column. Command CRUISE INHIBIT/ENABLE OFF. If test light illuminates, go to next step. If test light does not illuminate, go to step  26 .
  14. Using a DVOM connected to ground, probe cruise control module harness connector terminal "J" (Light Blue/Black wire). If battery voltage is present, go to next step. If battery voltage is not present, go to step  27 .
  15. Check speedometer for proper operation. If speedometer operates properly, go to step  28 . If speedometer does not operate properly, repair speedometer by symptom. See appropriate ANALOG INSTRUMENT PANELS article.
  16. Test for short to voltage in wire that caused test light to come on in step  3 . If no problem was found or condition still exists, go to step  34 . If problem is found repair as necessary. After repair, go to step  43 .
  17. Check Gray wire between cruise control functional switches harness connector and cruise control harness connector terminal "A" for open or high resistance. See Fig 1 . Repair circuit as necessary. After repair, go to step  43 . If no problem was found or condition still exists, go to next step.
  18. Check Pink wire between rear fuse block and cruise control functional switches harness connector for open or high resistance. If no problem was found or condition still exists, go to step  34 . If problem is found, repair Pink wire as necessary. After repair, go to step  43 .
  19. Check Dark Blue wire between cruise control functional switches harness connector terminal "C" and cruise control module harness connector terminal "B" for open or high resistance. If no problem was found or condition still exists, go to step  34 . If problem is found, repair Dark Blue wire as necessary. After repair, go to step  43 .
  20. Check Gray/Black wire between cruise control functional switches harness connector terminal "D" and cruise control module harness connector terminal "C" for open or high resistance. If no problem was found or condition still exists, go to step  34 . If problem is found, repair Gray/Black wire as necessary. After repair, go to step  43 .
  21. Check Purple wire between ABS/TCC (cruise control release) switch and cruise control module terminal "D" for open or high resistance. If no problem was found or condition still exists, go to step  29 . If problem is found, repair Purple wire as necessary. After repair, go to step  43 .
  22. Check Purple wire between cruise control ABS/TCC (cruise control release) switch and cruise control module harness connector terminal "D" for short to voltage. See Fig 1 . If no problem was found or condition still exists, go to step  29 . If problem is found, repair Purple wire as necessary. After repair, go to step  43 .
  23. Check White wire between cruise control module harness connector terminal "G" and brakelight switch for short to voltage. See WIRING DIAGRAMS  . If no problem was found or condition still exists, go to step  30 . If problem is found, repair White wire as necessary. After repair, go to step  43 .
  24. Check White wire between cruise control module harness connector terminal "G" and brakelight switch harness connector for open or high resistance. If no problem was found or condition still exists, go to step  30 . If problem is found, repair White wire as necessary. After repair, go to step  43 .
  25. Check Dark Green wire between cruise control module harness connector terminal "H" and Blue PCM harness connector C1 terminal No. 72 for short to ground. If no problem was found or condition still exists, go to step  33 . If problem is found, repair Dark Green wire as necessary. After repair, go to step  43 .
  26. Check Dark Green wire between cruise control module harness connector terminal "H" and Blue PCM harness connector C1 terminal No. 72 for open, high resistance or short to voltage. If no problem was found or condition still exists, go to step  33 . If problem is found, repair Dark Green wire as necessary. After repair, go to step  43 .
  27. Check Light Blue/Black wire between cruise control module harness connector terminal "J" and Clear PCM harness connector C2 terminal No. 59 for open, high resistance or short to voltage. See WIRING DIAGRAMS  . If no problem was found or condition still exists, go to step  33 . If problem is found, repair Light Blue/Black wire as necessary. After repair, go to step  43 .
  28. Check Dark Green/White wire between cruise control module harness connector terminal "K" and Blue PCM harness connector C1 terminal No. 55 for open or high resistance. See Fig 1 . If no problem was found or condition still exists, go to step  35 . If problem is found, repair Dark Green/White wire as necessary. After repair, go to step  43 .
  29. Check ABS/TCC (cruise control release) switch for proper adjustment. See ABS/TCC OR CRUISE CONTROL RELEASE SWITCH  under ADJUSTMENTS. If adjustment is okay and condition still exists, go to step  31 . Adjust ABS/TCC (cruise control release) switch if necessary. After adjustment, go to step  43 .
  30. Check cruise control brakelight switch for proper adjustment. See BRAKELIGHT SWITCH  under ADJUSTMENTS. If adjustment is okay and condition still exists, go to step  32 . Adjust brakelight switch if necessary. After adjustment, go to step  43 .
  31. Check for poor harness connections or connector damage at ABS/TCC (cruise control release) switch harness connector. If no problem was found or condition still exists, go to step  38 . If problem is found, repair as necessary. After repair, go to step  43 .
  32. Check for poor harness connections or connector damage at brakelight switch harness connector. If no problem was found or condition still exists, go to step  39 . If problem is found, repair as necessary. After repair, go to step  43 .
  33. Check for poor harness connections or connector damage at PCM harness connectors. If no problem was found or condition still exists, go to step  40 . If problem is found, repair as necessary. After repair, go to step  43 .
  34. Check for poor harness connections at cruise control functional switches. If no problem was found or condition still exists, go to step  41 . If problem is found, repair connections as necessary. After repair, go to step  43 .
  35. Check for poor harness connections or connector damage at cruise control module. If no problem was found or condition still exists, go to step  42 . If problem is found, repair as necessary. After repair, go to step  43 .
  36. Repair Pink wire between cruise control module harness connector terminal "F" and CRUISE fuse (10-amp) in underhood fuse block as necessary. See WIRING DIAGRAMS  . After repair, go to step  43 .
  37. Repair Black wire between cruise control module harness connector terminal "E" and chassis ground. After repair, go to step  43 .
  38. Replace and adjust ABS/TCC (cruise control release) switch. See ABS/TCC OR CRUISE CONTROL RELEASE SWITCH  under REMOVAL & INSTALLATION. See ABS/TCC OR CRUISE CONTROL RELEASE SWITCH  under ADJUSTMENTS. After repair, go to step  43
  39. Replace and adjust brakelight switch. See BRAKELIGHT SWITCH  under REMOVAL & INSTALLATION. See BRAKELIGHT SWITCH  under ADJUSTMENTS. After repair, go to step  43
  40. Replace PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION. Program PCM. See POWERTRAIN CONTROL MODULE PROGRAMMING  under PROGRAMMING. After repair, go to step  43 .
  41. Replace cruise control functional switches. See CRUISE CONTROL FUNCTIONAL SWITCHES  under REMOVAL & INSTALLATION. After repair, go to step  43
  42. Replace cruise control module. See CRUISE CONTROL MODULE  under REMOVAL & INSTALLATION. After repair, go to next step
  43. Operate vehicle within conditions for cruise control system operation. Fully test functionality of cruise control system. If cruise control system operates properly, system is okay. If cruise control system does not operate properly, return to step  2 .
Fig 1: Identifying Cruise Control Module Harness Connector Terminals
G00062237Courtesy of GENERAL MOTORS CORP.
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