If it is cycling on and off over a period of time it sounds like you have a leak in the system.
First spray the jacks with a solution of Simple Green, 1 to 5 ratio water to Green, and watch for bubbles. Simple Green will support very small bubble and those detect a very small leak.
If the jacks check out OK try around the pump and tank if so equipped and then you will have to work you way along to air lines spraying and looking.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles