Easiest is to make sure the clutch pedal is all the way up. Sometimes they stick a bit and won't trip the clutch switch. Also do check the clutch switch itself, make sure it is making proper contact with the clutch pedal and the wiring to the switch didn't get unplugged. Make sure your brake pedal is all the way up too, including the spike. Other than that you would have to plug in a computer to see which input the ECM is seeing or not seeing to prevent the cruise from working.