How to Troubleshoot & Replace Bosch AP4512904 / 00617229 Switch

I believe the problem was caused by a power surge when our electricity returned from an outage. FirstI removed the two screws on top and removed the vent. This exposes the one screw that holds the control panel in place. First I checked the fuse to see if blown but it was ok. Two screws hold the plastic. bracket in place that holds the 3 door switches. Uncouple the wires attached to the switches and pull the bracket out. Then carefully pull the switches out of the housing with a small screw driver. Replace and your good to go... 

It looked at first like failure of the middle of the three switches that sense the open/close status of the door. Replacing this restored function for a day or so, until the problem returned. I noticed that slight wiggling of the door could close and open this switch. Looking closely at the "lock" it appeared that the ramp that the door catches slid up were worn at the inside edge. The replacement part confirmed that the end of this ramp was worn. This apparently causes the sequence of switch closures to sometimes go wrong. It has only been a few days, but looks like replacing this part did the job. Why an expensive microwave would contain a part made of inadequate plastic, leading to failure in 5 years, is a good question. 

Microwave would trip the breaker when I would press start. So I looked on Google and found on Youtube which indicated it could be a door switch. "IMPORTANT I AM AN ELECTRICAL DESIGNER/ENGINEER THERE IS A CAPACITOR THAT HOLDS ELECTRIC ENERGY EVEN WHEN UNPLUGGED DO NOT DO THIS WORK UNLESS YOU KNOW WHAT YOU ARE DOING TO REMOVE THIS ELECTRIC ENERGY SAFELY" I took apart the microwave and behind the touch panel of the microwave was the wiring sheet. There are (2) switches on the door. I took a meter and check for continuity of the switches with door open and closed. What I saw in youtube was correct, it was the middle switch which is the door monitor. The bracket that these switches mount in seemed to have a broken clip on one of the switches. So I ordered all (3) new switches and the bracket with spare fuse. When parts came in, I replaced everything verified the switches worked correctly with my meter again then did a test before remounting. It worked! $50 buck vs 200+ for a service guy or more to replace microwave. 

Removing the top grill allows access to the control panel. 3 screws total. Carefully remove the connectors making sure you write down where each one goes. With the panel out of the way, two more screws allow the removal of the bracket that holds the three door switches, and allowing you to replace the faulty one. Each switch is held into the bracket by a plastic tab that when moved away will allow each switch to slide out. The broken one will be discolored or have a button that lost it’s spring. The switches are slightly different, so make sure you know which one to order. They operate in opposite function, ie open/closed circuit. There may be a schematic diagram that will help identify the correct function and location for ordering. If you are truly proactive, you might want to order and replace all three. Installation is easy, by simply reversing each step. 

I changed the filter module and the 3 door micro switches and their holder to be safe. 

Open the microwave and found the 20 amp glass fuse blown. Checked all three door switches and one had failed. Replaced switches and replaced the fuse and everything worked perfectly. 

Searched online for similar problems. Tested door latch switches with a continuity tester. Removed the control panel and identified the faulty switch. Followed online instructions for replacement 

The middle Door Switch was actually bad. Replaced all 3 switches any way's. Going to order another set of switches and bracket just for a spare. Service was fast and the FedEx delivery. 

I replaced the door switches and the holder for the switches. I probably did not need all of the switches, however I wanted to rebuild the entire assembly so as I would not have to replace them one at a time. You could replace just the switch that is bad, you would need to take it apart and test each switch to determine which one is bad, then order that switch, so you would need to take it apart twice. Watched a video on YouTube on the replacement of the switches, the parts were all correct from AppliancePartsPros.com Thank you. 

My microwave was blowing the circuit breaker. I replaced the door switches on my Bosch microwave before with the same problem. The switches couldn't be just wearing out. The "normally open" and "normally closed" switches must be tripped at the same instant. If they don't it burns the switch and trips the breaker. I noticed that there was excessive play / a loose fit of the switch in the plastic bracket attached to the door frame. I shimmed the new switch so it didn't move. That should solve the problem.