Cruise Control Inoperative
- Turn cruise control off. Disconnect cruise control module. Turn ignition on. Connect a test light between cruise control module 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 or Pink wire.
- 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 in Black/White wire.
- 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 next step. If test light does not glow, 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. See STEERING COLUMN SWITCHES
article.
- 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. See STEERING COLUMN SWITCHES
article.
- 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 circuit to Dark Blue wire. If circuits are okay, check for poor connection at multifunction lever. If connection is okay, replace multifunction lever. See STEERING COLUMN SWITCHES
article.
- Connect test light between cruise control module connector terminals "E" (Black wire) and "D" (Purple wire). If test light does not glow, go to next step. If test light glows, go to step 8).
- Using test light, backprobe between cruise control brake switch connector terminal "B" (Dark Blue wire) and ground. If test light glows, repair poor connection or open circuit in Purple wire. If test light does not glow, check for poor connection or open in Brown wire between cruise control brake switch and fuse block. Also check cruise control brake switch for correct alignment. If circuit and switch alignment are okay, replace cruise control brake switch.
- If test light came on in step 6), set parking brake. Raise drive wheels. Using Digital Voltmeter/Ohmmeter (DVOM), measure voltage between cruise control module connector terminal "K" (Dark Green/White wire) and ground. While observing voltmeter, rotate drive wheels by hand. If voltage varies, go to next step. If voltage does not vary, repair poor connection or open in Dark Green/White wire.
- Turn ignition off. Check for a poor connection or open in Dark Green wire between PCM and cruise control module. Repair as necessary. Reinstall cruise control module. Attach a scan tool to Data Link Connector (DLC). Start engine. Clear any codes. Attempt to operate cruise control. If scan tool displays SMCC INHIBITED, see TESTS W/CODES
article in ENGINE PERFORMANCE section. If scan tool does not display SMCC INHIBITED, go to next step.
- Clear all codes. Select Mode 4 diagnostics on scan tool. Command SMCC to allow cruise. Using DVOM, measure voltage between cruise control module connector terminal "H" (Dark Green wire) and voltage. If about battery voltage exists, replace cruise control module. If about battery voltage does not exist, check for a short to power in Dark Green wire. If circuit is okay, check PCM. See TESTS W/CODES
article in ENGINE PERFORMANCE section.
Courtesy of GENERAL MOTORS CORP.