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does this happen when its rerfilling with water in between the cycles? Do you have the model number?
Well this can be a little difficult but if you really handy you can probably do it, there is a nut (plastic) that holds it on to the tank you need to take the nut off and a few wires and install the new one, here is a link to all the parts and diagrams for your machine,
http://www.searspartsdirect.com/partsdirect/part-model/Whirlpool-Parts/Dishwasher-Parts/Model-DU1055XTVQ1/1198/0130000?pathTaken=&prst=0&shdMod=DU1055XTVQ1 hope this helps, thanks, Bryan