That last post tells me the pump runs and the "bow" (the part of the top that contains the rear window) raises - but it does not go any farther. IF I have this right, then:

• If the pump still runs, but nothing is moving - I'd say you have low fluid (which also means you have a leak somewhere)
• If the pump quits running when the bow goes up and nothing more happens, I'd guess a travel sensor on one of the cylinders is bad.