If the door handle appears loose, you could have a broken door latch which will prevent the dishwasher from running if the door is not able to latch properly. The latch usually has two micro switches that are pretty delicate. Not to accuse you of abusing your appliance, but if you're in the habit of slamming the dishwasher door shut, you could inadvertently break the switches in the door. The switch assembly and handle are sold separately, so you may need to purchase both. Let me know if this helps.
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