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Cruise Control Inoperative

NOTE: To avoid misdiagnosis, ensure preliminary inspection and all checks have been performed. See TROUBLE SHOOTING  .
  1. Place cruise control switch in OFF position. Disconnect Cruise Control Module (CCM) harness connector. Turn ignition on. Using test light connected to ground, probe CCM connector (harness side) terminal "F" (Brown wire). See Fig 1 . If test light illuminates, go to step  3 . If test light does not illuminate, go to next step.
  2. Repair poor connection or open in Brown wire between CCM connector terminal "F" and instrument panel fuse block.
  3. Connect test light between CCM connector (harness side) terminals "F" (Brown wire) and "E" (Black wire). See Fig 1 . If test light illuminates, go to step  5 . If test light does not illuminate, go to next step.
  4. Repair poor connection or open in Black wire between CCM connector terminal "E" and ground connection G104.
  5. Using test light connected to ground, probe multifunction lever 48-pin harness connector C202, terminal E1 (Brown wire). If test light illuminates, go to step  7 . If test light does not illuminate, go to next step.
  6. Repair poor connection or open in Brown wire between multifunction lever 48-pin harness connector C202, terminal E1 and instrument panel fuse block.
  7. Place cruise control switch in ON position. Using test light connected to ground, probe multifunction lever 48-pin harness connector C202, terminal E2 (Gray wire). If test light illuminates, go to step  9 . If test light does not illuminate, go to next step.
  8. Check multifunction lever harness connector for a poor connection. Repair as necessary and retest system. If connection is okay, replace multifunction lever (cruise control switch). See appropriate STEERING COLUMN SWITCHES article.
  9. Using test light connected to ground, probe CCM harness connector (harness side) terminal "A" (Gray wire). See Fig 1 . If test light illuminates, go to step  11 . If test light does not illuminate, go to next step.
  10. Repair open or short to ground in Gray wire between multifunction lever harness connector C202, terminal E2 and CCM harness connector terminal "A".
  11. Using test light connected to ground, probe multifunction lever 48-pin harness connector C202, terminal E3 (Dark Blue wire). Press and hold SET button on multifunction lever. If test light illuminates, go to next step. If test light does not illuminate, go to step  8 .
  12. Using test light connected to ground, probe CCM harness connector (harness side) terminal "B" (Dark Blue wire). See Fig 1 . Press and hold SET button on multifunction lever. If test light illuminates, go to step  14 . If test light does not illuminate, go to next step.
  13. Repair open or short to ground in Dark Blue wire between multifunction lever harness connector C202, terminal E3 and CCM harness connector terminal "B".
  14. Using DVOM connected to ground, measure voltage at CCM harness connector (harness side) terminal "G" (Light Blue wire on Bonneville; White wire on Eighty Eight, LeSabre and LSS). See Fig 1 . If reading is .5 volt or greater, go to next step. If reading is less than .5 volt, go to step  16 .
  15. Repair short to voltage in Light Blue wire on Bonneville; or White wire on Eighty Eight, LeSabre and LSS between CCM harness connector terminal "G" and brakelight/BTSI switch harness connector C2, terminal "B".
  16. Using DVOM connected to ground, measure voltage at CCM harness connector (harness side) terminal "D" (Purple wire). Depress and release brake pedal while observing voltage reading. Reading should be .5 volt or less with brake pedal depressed, and 10-15 volts with brake pedal released. If reading is as specified, go to step  22 . If reading is not as specified, go to next step.
  17. Turn ignition off. Disconnect ABS/TCC switch harness connector. See Fig 2 . Using DVOM connected to ground, measure voltage at ABS/TCC switch harness connector terminal "A" (Brown wire). Turn ignition on. If reading is 10-15 volts, go to step  19 . If reading is not 10-15 volts, go to next step.
  18. Repair open or short to ground in Brown wire between instrument panel fuse block and ABS/TCC switch harness connector terminal "A".
  19. Turn ignition off. Connect DVOM between ground and CCM harness connector terminal "D" (Purple wire). See Fig 1 . Connect fused jumper wire between ABS/TCC switch harness connector terminals "A" and "B". Turn ignition on. Observe voltage reading. Remove jumper wire and note voltage reading. Reading should be 10-15 volts with jumper wire connected, and less than .5 volt with jumper wire removed. If readings are as specified, go to step  21 . If readings are not as specified, go to next step.
  20. Repair open, short to ground or short to voltage in Purple wire between ABS/TCC switch harness connector terminal "B" and CCM harness connector terminal "D" or PCM harness connector C1, terminal No. 30.
  21. Check for poor connection at ABS/TCC switch harness connector. Repair as necessary and retest system. If connection is okay, replace ABS/TCC switch. See ABS/TCC SWITCH  under REMOVAL & INSTALLATION.
  22. Set parking brake. Raise and support drive wheels. Connect DVOM between ground and CCM harness connector terminal "K" (Dark Green/White wire). Rotate drive wheels by hand while observing voltage reading. If voltage varies as drive wheels are rotated, go to step  24 . If voltage does not vary as drive wheels are rotated, go to next step.
  23. Repair open in Dark Green/White wire between CCM harness connector terminal "K" and PCM harness connector C1, terminal No. 55.
  24. Turn ignition off. Reconnect CCM harness connector. Disconnect PCM harness connector C1. Connect DVOM between ground and PCM harness connector C1, terminal No. 72 (Dark Green wire). Turn ignition on and observe voltage reading. If reading is 10-15 volts, go to step  2 . If reading is not 10-15 volts, go to next step.
  25. Check for open or short to ground in Dark Green wire between PCM harness connector C1, terminal No. 72 and CCM harness connector terminal "H". If Dark Green wire is okay, go to step  3 . If Dark Green wire is not okay, go to next step.
  26. Repair open or short to ground in Dark Green wire between PCM harness connector C1, terminal No. 72 and CCM harness connector terminal "H".
  27. Turn ignition off. Reconnect PCM harness connector C1. Disconnect CCM harness connector. Turn ignition on. Using scan tool, clear DTCs. Select PCM SPECIAL FUNCTIONS, ENGINE OUTPUT CONTROLS, and then CRUISE INHIBIT. Using DVOM connected to ground, measure voltage at CCM harness connector terminal "H" (Dark Green wire). Observe voltage reading while commanding PCM to turn cruise inhibit OFF (NO) and ON (YES). Reading should be 10-15 volts with cruise inhibit OFF, and less than .5 volt with cruise inhibit ON. If reading is as specified, go to step  29 . If reading is not as specified, go to next step.
  28. Check CCM harness connector for poor connection. If connection is okay, replace CCM. See CRUISE CONTROL MODULE  under REMOVAL & INSTALLATION.
  29. Diagnose PCM. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
Fig 1: Identifying Cruise Control Module (CCM) Harness Connector Terminals
G99E02303Courtesy of GENERAL MOTORS CORP.
Fig 2: Identifying ABS/TCC Switch, Brake Switch & Cruise Control Release Switch
G98B01095Courtesy of GENERAL MOTORS CORP.
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