The pressure switch is a under rated micro switch for amps. I've replaced it several times. Took switch out, looked up the part number, bought several on Ebay.
Then I got tired of replacing micro.
So I bought a heavy duty 30+ amp automotive relay. Now the underrated microswitch powers the heavy duty relay that powers the motor.
My fix was a few dollars versus a new pump for $50+.
2015 Fleetwood Discovery 40E on a Freightliner XCS chassis with a Cummins ISL9 pulling 1 and/or 2 motorcycles, '07 Honda Accord OR a 17' Runabout Boat.