Whirlpool ADP5540 no spray

[Video]

Whirlpool ADP5540 dishwasher
water goes in, pumps out, heats up, but spray arms not working.
I pulled the pump out, and when connected independantly it works fine but when installed back in the dishwasher it won't work.
Any sugestions?

 

[assuhors]

If the wash pump is a Plaset and looks like a large drain pump,the impellor becomes detatched and although it sounds ok wont actually pump water.The replacement wash pumps are made by Ceset and although look different are interchangeable.