Find a power supply that puts out 12v. You could use an old wall adapter for a kid's toy, an old battery charger, or anything that puts out 12v. Don't worry about milliamps, you're only driving a relay, and they have almost no draw. These things are everywhere, thrift shops, garage sales, ect. Get an outlet and box with cover plate and use sheet metal screws to attach it to the frame of the pump. Connect line voltage to the outlet, install wall cover on outlet. Plug in wall adapter. You now have 12VDC inside the pump. Find a 12V relay rated for 120v output. Wire one side of the coil wiring to one wire from the adapter. Run a double strand wire through the hose to the nozzle. Connect both wires to your switch. Back in the pump connect one wire to the leftover wire from the adapter to the nozzle wire. Connect the other wire from the nozzle to the other coil lug on the relay. Connect 120v hot wire from your line into the pump to the normally open POSTof the relay. Connect the wire to the motor to the POLE of the relay.