Cruise control dump valves should hold vacuum and have continuity across their pins when the brakse and clutch pedals are released. A quick check for the vacuum if it is the valves slightly out of adjustment is to lift up on the pedals and see if the little bit more is enough to make them seal. If it doers, then adjustment is usually enough to take care of them. If pulling the pedal up doesn't get the system to hold vacuum, you should still inspect the dump valves
