A control (60) that mounts in a space (52) between main vehicle parts (66, 68) that are supported one on the other by air bags (16). The control includes first and second vertical tubes (82, 106) that telescope in one another. The tubes enclose at least parts of valves (98, 111) and passages (84, 104, 101, 103) that connect the valves to inlet, exhaust and air bag ports (74, 76, 80).