Slimline Dishwasher not cleaning dishes? How to change flow through heater element.

Bush WV9-6W Slimline Dishwasher not cleaning dishes well. Diagnosed as water heater element malfunction.
How to take apart, test and diagnose, then change the flow through heater and heating system parts.
(Credit: Elena W, Camera Operator)

[@ricardosancho85]

Could you provide a link to where you got the pressure switch? Thanks

[@yorkshiregunner9820]

Mines that model but it starts and then stops.any help please