Hi-Lo forum is best place to pose this question. If pump runs when switch is pressed to raise and will not lift, you have a leak or stuck relief valve or bad pump or stuck lowering valve or the lift cylinder by passing fluid internally at the cylinder piston seals. Hi-Lo uses a very basic hydraulic circuit. Lots of or's, but easy to check each one.
I am a former Hi-Lo owner and hydraulic engineer.
2020 RENEGADE VALENCIA 38RW
2017 JEEP JK