How to Troubleshoot & Replace Whirlpool AP5950105 / W10727360 Door Switch

I have a Kitchenaid KMHC319ESS-0. On this model, the keypad is on the door, and the entire microwave front surface is one big door. I didn’t find any helpful illustrations or movies on the internet for this model, but I can share that it is unnecessary to uninstall the unit for door switch replacement. If you open the door, there are 3 screws holding the plastic indoor vent; remove those and the plastic, then the fourth, single screw holding the vertical plastic piece on the right of the microwave, then slide this piece up to disengage the tabs. From this point on, switch replacement is like what you see in the videos. If you are careful, you can save $ by buying three of the w10727360 switches instead of those two $20 switches. The left position of the top assembly has connections to all three switch terminals (common, NO, NC) but the right top switch and lower switch only have two of their terminals used. Carefully note in each case whether the connections are to the NO or NC terminal (they are marked on the switch body), then wrap a piece of electrical tape around the unused terminal and install. One piece of advice is to disconnect the wires so that the switch assembly is completely free of the microwave before trying to remove the switches from the assembly - it will make it much easier to not break the mounting tabs. When reassembling the plastic vent, either a pair of needle nose pliers or a magnetized screwdriver is needed to get that rightmost screw in place. This is only speculation on my part, but it appears that opening the door (for example) doesn’t hold one switch state until the door is subsequently closed, but instead cycles the switch, and the switch output looks like a logic state change to the computer. If you inspect the mechanism, you can see a bump on the switch actuator so that in the process of closing the door, the little button on the actual switch is depressed then released, not held in the alternate position. I bring this up because a switch that is sluggish might appear functional if checked with an ohmmeter, but it has to respond quickly when the plastic bump goes by, or the computer won’t get the correct information from the switch. 

It is difficult (if not impossible) to remove the electronic switches from the hard plastic latches. I replaced all three switches and both the upper and lower latches I also replaced the main 20 amp ceramic fuse which blew out when the latch/switches failed. 

Replaced door switch. The part from Appliance Pros came fast. Also replaced microwave fuse I blew. 

I replaced the three switches and two supports inside the control panel. 

Google search turned up hints that it could be one of the door interlock switches gone bad. Further research showed how to access them. Found the bad switch and in the process of removing it from the bracket I snapped off one of the switch hold down prongs (there was a warning about this but the plastic is very brittle and easy for this to happen without extreme care and likely having a helper). Found the parts on a number of sites but only AppliancePartsPros had both and they were in stock. The delivery blew me away.. ordered late day on a Thursday and was here on Friday. Awesome! Repair went smooth but be sure to draw wire diagrams. Mine had 3 door interlock switches and god help you if you mix up the wiring. 

Replaced the 3 micro switches and the switch interlocks. I would recommend when changing these out to purchase the new interlock holders. The microswitches snap in place but when try to remove the side clips snap. For the extra 20.00 for both interlock holders well worth it. I had to order after the fact but received the next day. Within 30 minutes I was done and microwave works perfectly. Thanks for the great prompt service. 

One of the 3 switches was not working consistently. Of course it was the one that was hardest to get at. Had to remove the keypad panel (one screw at the top), and then push up the panel to remove. There’s an inside plastic shield with two screws to remove as well. Had to unscrew the top switch interlock star screw to get at the switch that was defective. Manually activated the switches on and off with a screwdriver. The good ones had a crisp click, and the bad one made a softer click and sometimes didn’t click at all. Confirmed it was defective with a multi tester for continuity. Replaced switch. Now working. Broke one of the two tabs when removing the switch, so had to replace interlock support and cam as well. So be gentle! 

Replaces all 3 micro switches. Not first time I had to do this. 

Ordered all new door switches and a ceramic fuse. Replacing fuse brought it back to life. Upon initial testing, operation was good and repeatable, so I forwent the switch replacement and later used the machine to cook (3) sweet potatoes (at once) using the "Potato" auto sensing button. It then threw an "F4E4 Humidity Sensor" error code. I'm assuming other auto features are either bugged or broken, as well, but standard operation via number pad is dependable so far. Cooked the potatoes for 9 minutes with no issues. I'm also assuming my problem likely lies in the circuit board, not the switches, and whether or not that was the initial culprit or if I caused it when blowing the fuse is anybody's guess. If replacing the board is cost and skill friendly, I'll likely swap out the switches at time of that repair. 

I have background in electrical repair so I figured it was one of the micro switches that are in the door latches. On disassembly the upper switch came apart in my hand. I could not find a local distributor of these so I contacted Repair parts Pros. They had the parts, but oddly one switch was $22.00 or so while the other only $3.50. When I received the switches (which arrived promptly) I noticed that the cheaper switch was more of a universal type, (could be normally open or normally closed depending on the contacts used) while the more expensive one was more like OEM with only two contacts. fact is, the cheaper one would have worked in both applications but the installer would have to know how to determine which contacts to use. I had to use a multi-meter to determine which two contacts to use on the lower switch as one is NO and the other NC. No big deal but a less experienced person may have had a problem.