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Cruise Control Will Not Engage

  1. Turn ignition off. Disconnect cruise control module connector. Turn ignition on (engine off). Connect test light between connector terminal "F" (Brown wire) and ground. See Fig 1 . If test light glows, go to next step. If test light does not glow, repair poor connection or open circuit in Brown wire.
  2. Connect test light between cruise control module connector terminals "F" (Brown wire) and "E" (Black wire). If test light glows, go to next step. If test light does not glow, repair poor connection or open circuit in Black wire.
  3. Turn cruise control on. Connect test light between cruise control module connector terminals "E" (Black wire) and "A" (Gray wire). If test light glows, go to step 6). If test light does not glow, go to next step.
  4. Connect test light between cruise control module connector terminals "E" (Black wire) and "B" (Dark Blue wire). While observing test light, press and hold SET/COAST switch. If test light does not glow, go to next step. If test light glows, check for a poor connection, short to ground or open in Gray wire between cruise control module and multifunction lever. If circuit is okay, replace multifunction lever.
  5. Check for a poor connection or open in Brown wire between multifunction lever and fuse block. If circuit is okay, replace multifunction lever.
  6. Connect test light between cruise control module connector terminals "E" (Black wire) and "B" (Dark Blue wire). While observing test light, press and hold SET/COAST switch. If test light glows, go to next step. If test light does not glow, check for a poor connection, short to ground or open in Dark Blue wire between cruise control module and multifunction lever. If circuit is okay, replace multifunction lever.
  7. Connect test light between cruise control module connector terminals "E" (Black wire) and "C" (Gray/Black wire). While observing test light, press and hold SET/COAST switch. If test light does not glow, go to next step. If test light glows, check Gray/Black wire for a short to Dark Blue wire. If circuit is okay, replace multifunction lever.
  8. Connect test light between cruise control module connector terminals "E" (Black wire) and "D" (Brown wire). If test light does not glow, go to next step. If test light glows, go to step 10).
  9. Backprobe with a test light between cruise control release switch connector terminal "B" (Brown wire) and ground. If test light glows, repair poor connection or open in Brown wire between release switch and cruise control module. If test light does not glow, check for a poor connection or open circuit in Brown wire between release switch and fuse block. If circuit is okay, check cruise control release switch for correct alignment. If alignment is okay, replace switch.
  10. Connect test light between cruise control module connector terminals "E" (Black wire) and "B" (Dark Blue wire). If test light does not glow, go to next step. If test light glows, check for a short to power in Dark Blue wire. If circuit is okay, replace multifunction lever.
  11. Connect test light between cruise control module connector terminals "E" (Black wire) and "C" (Gray/Black wire). If test light does not glow, go to next step. If test light glows, check for a short to power in Gray/Black wire. If circuit is okay, replace multifunction lever.
  12. Set parking brake. Raise and support vehicle. Using Digital Voltmeter/Ohmmeter (DVOM), check voltage between cruise control module connector terminal "K" (Dark Green wire) and ground. Rotate drive wheels by hand. If voltage fluctuates between zero and 5 volts, go to next step. If voltage does not fluctuate between zero and 5 volts, repair poor connection or open in Dark Green wire between cruise control module and PCM.
  13. Turn ignition off. Check for a poor connection or open in Dark Green wire between cruise control module terminal "H" and PCM. If wire is okay, reinstall cruise control module. Install scan tool to Data Link Connector (DLC). Start engine. Clear any existing Diagnostic Trouble Codes (DTCs). Operate cruise control. If scan tool displays SMCC INHIBITED, go to next step. If scan tool does not display SMCC INHIBITED, go to step 16).
  14. Using scan tool, monitor following parameters:
    • VSS should be 25-100 MPH.
    • Transmission range should be second, third or fourth gear.
    • System voltage should be 9-17 volts.
    • Engine speed should be 500-5400 RPM.
  15. If parameters are within range, PCM is not operating correctly. If parameters are not within range, check vehicle on-board diagnostic system. In both cases, see appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. Refer to menu below.
  16. Clear any DTC that may have set. Using scan tool, select Mode 4. Command SMCC to allow cruise. Using DVOM, check voltage between cruise control module connector and battery voltage. If battery voltage exists, replace cruise control module. If battery voltage does not exist, check for short to power in Dark Green wire between cruise control module terminal "H" and PCM. If wire is okay, check PCM. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. Refer to menu below.
Fig 1: Identifying Cruise Control Module Connector Terminals
G95J12517Courtesy of GENERAL MOTORS CORP.
IDENTIFYING MODULE CONNECTOR TERMINALS

Terminal Wire Color Function
A GRY Cruise ON/OFF Input
B DK BLU SET/COAST Switch Input
C GRY/BLK RESUME/ACCEL Switch Input
D BRN Release Switch Input
E BLK Ground
F BRN Fused Ignition Feed
G WHT Stop Light/TCC Switch Input
H DK GRN Cruise Inhibit Signal
J WHT Cruise Engaged Signal
K DK GRN VSS Signal - 4000 Pulses/Mile
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