The pump is 12vdc, id check to see if you have 12v at the pump wires with the switch on. If theres 12v to pump and not running then theres an issue with the pump. Id guess either a loose wire, bad pressure switch ( also on the pump assembly) bad pump or corrosion on the connections. If no 12v you have either a power wiring or on off switch issue. Id also check for 12v on both sides of the fuse with a test light to know its passing power.
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