My name is ***** ***** I am a professional here at Just Answer. I noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.
Below are some links you can copy and paste into a new web page or web tab to view the cruise control diagnostic procedure for your exact model here.If this doesn't help you locate the fault let me know.
IMPORTANT: Perform the following in order to avoid misdiagnosis.
^ Inspect for proper operation of brake lamps.
^ Inspect throttle linkage for mechanical binding which could cause the system to malfunction.
^ Inspect cruise control cable adjustment, should have minimum slack.
^ Inspect for stored Diagnostic Trouble Codes (DTCs) in the PCM. Refer to A Powertrain On Board Diagnostic (OBD) System Check in Engine
^ EMI on the speed sensor signal circuit may cause erratic cruise control operation.
CONDITIONS FOR ENABLING CRUISE CONTROL
^ When vehicle speed is more than 40 km/h (25 mph)
^ When PARK, REVERSE, NEUTRAL, or 1st gear is not indicated by the Park/ Neutral Position Switch.
^ When an over/undercharged battery condition does not exist.
^ With normal engine RPM.
^ Without high engine RPM (fuel cut-off). Refer to Fuel Metering Modes of Operation in Engine Controls for additional information.