High Limit Thermostat 154290204

Unplugged the dishwasher. Closed and disconnected the water supply. Removed two screws that attached the dishwasher to the countertop. Pulled the dishwasher out from underneath the countertop. Laid the dishwasher on its side to access the bottom. The high limit thermostat had shorted out and showed signs of electrical burn. I removed the high limit thermostat by unscrewing the single screw that holds it in place. I then pulled the two electrical terminals off the high limit thermostat . One terminal (i.e. small electrical plug connecting electrical wire to high limit thermostat) was burned badly. I cut it off the wire and attached a generic terminal bought at local hardware store (six for $3). The other terminal was fine. I plugged the new high limit thermostat in and attached it with the single screw to the dish washer. Put the dishwasher back in place. Test ran dish washer and dishes came out shiny, clean and dry. Done.

Disconnected power to the unit at the circuit breaker. Removed the bottom panel of the dishwasher. Used a stubby Phillip screwdriver to remove the single retaining screw holding the high limit thermostat against the bottom of the dishwasher tub. Not only was the thermostat burned out, one of it's electrical connectors was also destroyed. Removed the tape holding the cable bundle together so that I could work on the quick disconnect plug outside of the unit. One end of the quick disconnect plug was completely burned through and needed to be replaced. After doing the necessary electrical repairs and assembling the new thermostat into position I applied power and everything worked fine. It helped having a picture on your website that I could use to identify the correct replacement part.

As another poster had written, on terminal on the thermostat was burned off, most likely due to poor contact by the female spade connector on the end of one of the wires. Removed the DW, tipped it back to gain access, removed the failed thermostat, installed the new one, crimped a new terminal on the end of the wire, and re-installed the DW. Tested all cycles with the heat on and everything worked as designed. Very simple repair, took more time to get the DW out and put it back in than to replace the part and repair the wire.

Internet search found high limit switch as primary failure, removed dishwasher existing part looked new, no signs of wear as was expected. Second failure was the heating element, I ordered the part; At the same time I found a random youtube video, that had me check the continuity of the heater and tested good. Then the video indicated the heater relay may have one leg that has lost the solder and stops the heater element from working. I took the control panel a part and the heater relay had the same failure, one leg had a missing solder joint. Using some flux, solder and soldering iron I repaired the connection and added some addition solder to the circuit. Reassembled and the dishwasher is heating as it was before everything is working as expected!
(P.S. The heater relay failure appears to be a common problem, but the actual root cause [relay failure due to poor solder joint] is never reported back to the company, they just hear the heater element stopped working and they never fix the real issue because the customers are throwing out the dishwasher, when it could have been repaired with a simple fix. More importantly it should be something that is investigated as it may needs an engineering redesign. but can't fix what you don't know about or fail to investigate. I did purchase a new relay to replace the existing one, to be installed upon arrival).
Once again a random youtube video identifies and resolves a problem, that would have had me purchasing a new dishwasher, and maybe this is all planned engineering obsolescence.
When will get smart dishwasher that have sensors or at least codes that report the failures correctly, to make DIY repairs?

I removed the kick panel at the bottom front of the dishwasher. Then using a flashlight and a cross point screwdriver, I removed the thermostat from about the middle left. It requires a short screwdriver, but not quite as short as a stubby. I unplugged the wires, noting that one of them was a little burnt looking. The burnt looking connector was still okay. I then installed the new one, with the green dot on the thermostat having the slightly burnt looking connector. Then I ran a load of dishes and the dishwasher worked as it was supposed to. It has worked okay twice since then.

Removed dishwasher and looked for component that had gotten hot. Saw partially melted connector on thermostat. Removed and replaced thermostat. Replaced female spade connector on wire. Replaced dishwasher.