Your comment about it raising an inch or two makes me think you either have an open (or leaking) manual lowering valve or, you have an internal leak in the hydraulic system that is allowing the hydraulic fluid to escape back into the reservoir.
I'd check the manual lowering valve first. I'd actuate it full open then closed a few times to maybe free up any dirt in it. Then run the pump with it full open to force anything out before closing it and trying to lift the top again.
If it still just goes up partway, you either are low on hydraulic fluid or have a leaking seal. If it's low on fluid, add Dexron II-V. DO NOT add Dexron VI (6), it is an incompatible formulation, that I think will damage the seals.
Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter
2014 F150 Platinum 4x4 3.5L EcoBoost SCrew