Thermistor tests infinity. Picture shows o-ring. To remove from bottom of tub do I pull, or twist 90 degrees and pull. I do not want to cause a leak. Also, is a blown thermistor a natural event or is there an underlying cause that could cause the new one to “blow”? I assume that two leads are interchangeable on thermistor.
Here are your parts
Replacement parts for WHIRLPOOL GU1500XTKB0 Undercounter Dishwasher | AppliancePartsPros.com
Here is a manual
https://secured.whirlpool.com/Service/SrvTechAdm.nsf/2cd44500d572193285256a45004fd9d6/52521bdbd0ef763c85256cbc00520548/$FILE/8178022.pdf
See page 22.
Odds are it just blew on its own.
Note: I always put a light coating of lithium grease on Orings and seals when replacing them. Makes things go in a little smoother