Have you tried pressing the cruise control button on the dash?
Check ignition switch, common problem.
My 2002 Olsmobile Intrique cruise control works some times when you set it, why?
check fuse. they are all conected.
If the cruise control on your 1987 300ZX does not work, you might have an issue with the cruise control fuse or wiring. You could also have a problem with the switch that turns the cruise control on and off.
cruise control does not work on 98 astro van
check out the selinoid on the trunk latch
Cruise will NOT work if the speedometer has a problem
5W30 will work in all American climates
the crusie control band is probly broken
cruise control does not work when headlights are on
probably a broken wire, either at the switches, or in the steering column
If the AC is Blowing cold and turn off and on, the AC/heater control switch is bad. Replace it on eBay for around fifty dollars. Work great now.