Cruise Control is mostly not working, though occasionally it seems to take hold, but not for long. Is this system vacuum driven (possibly a bad vac hose) or am I looking for a control module of some sort? The indicator lamp in the dash switch comes on OK, and with intermittent operation I am assuming no fuse problems. Any thoughts?

 

Check all the vacuum hoses at the pump as well as the brake switch by the brake pedal arm, if one is leaking you won't engage.