Dishwasher -- repair of heater/thermostat?

Hello all,
I have a five-year-old Whirlpool dishwasher. Model GU1500, in case it matters significantly.
Of late, its performance has dropped significantly. The post-cycle dishes are often not, in fact, clean. It's not uncommon to find grit on some items. Cycles now take well over double the indicated time to complete -- just tonight, a "Normal" cycle claimed it would complete in 70 minutes, and it ran 2.5 *hours*.
While it runs, it spends a great deal of time with the "heating water" light on, and during that time it's LOUD. Loud enough that it keeps me awake, where I used to celebrate the quiet dishwasher and happily set loads to run in the wee hours.
A while back we had the home warranty guy out, but they were useless. Apparently they can't "fix" unless it's "broken", where "broken" is defined as a cycle which never advances, or takes many hours to complete.
After reading the included diagnostic sheet, I suspect that something in the water heating system is kaput. Perhaps the thermostat, thermister or the heating element itself? Or the fuse?
I'm curious if anyone has tackled this, and can advise on the viability of attempting a home repair. I'm not opposed to buying a new dishwasher, but geez louise I was figuring on a lot more than five years out of this one.
Thanks, Andrew
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Andrew Laurence snipped-for-privacy@uci.edu
Central Computing & Security http://www.nacs.uci.edu/~atlauren /
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Depends on your skill set. There are parts diagrams online that show lblowups of the unit at most of the places that sell parts. Also, there are service manuals available that cover groups of models.
It should be easy to check the heater element with a multimeter. If it's open or a high resistance, you will know it's bad. An even easier test is to put in on the heated dry mode. If the dishes get dry compared to a wash where it's off, you know the heating element is good. From the symptoms, that's where I would start. And you can replace a heating element easily and a new one should be reasonable. If you have to call someone to diagnose and fix it, then it gets very questionable, vs buying a new one.
Also, it's possible it's something entirely different and this is just a symptom, not the cause. For example, some of the new ones measure dirt in the water and will keep cycling to get it clean. So, if something else is wrong, it could still be running longer heating cycles.

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