Do your 12 volt lights work? It is going to require troubleshooting the system with a voltmeter to see where you have voltage and where you don’t. If you can’t do that you will need someone who can.
You need to make sure you have voltage (+12) at the load side of your fuses.
If so, you need to see if you have constant voltage at the switch common terminal.
If so, you need to see you have voltage at the other terminals when you actuate the switch.
If so, you need to see if you have voltage at the circuit breaker feeding the hydraulic pump.
If so, you need to see if you have voltage at the center terminal on top of the hydraulic pump.
If voltage at all points then you should hear a click from the black box on the pump when someone actuated the switch.
And the pump should start running after the click.
And as I mentioned, you should be able to open the slides using a reversible drill until you solve the power problem.
Did you recently install the new battery? It is possible the battery wiring was reversed.