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this could be a couple of different things, 1 the heater may be bad, 2 the board may have a burnt contact which is common. The first thing you should do is check the control board in the control panel, check for any burned solder joints, if they are all good replace the heater, you will need to pull the machine out from under the counters to get to the heater which is in the back right corner when you remove the side of the machine, you can order this at the following link if needed, http://www.repairclinic.com/PartDetail/Heating-Element/480317/935753?modelNumber=SHX46A05UC%2F43 .
Bryan, how do you access the control board/control panel of the specific dishwasher? Moreover, is this a quick fix or recommend for a service technician. Thanks!