How to Troubleshoot & Replace Lg AP4437957 / 3B73362F Microwave Door Switch

Replaced microwave door interlock switch. 

It seems that the door catch has 2 switches on the part that catches the door when you close it. If any of the 3 switches dont work the microwave will not start up and run. I took off the cover and then found the 3 switches. It was interesting in that getting out the switch you have to push back a plastic retainer and then twist the switch on its pivot point to get it out. The switches have a prong on them and they are attached to the electric line by a female slip on connector. They are very difficult to get off. Once off I tested the switch for continuity. Two were fine as they showed continuity when pushed but one was not allowing current to flow when it was pushed. I looked at the part diagram for my model number and ordered it from appliancepartspros.com as I have done with other appliances that needed repair. They sent me the part and I installed it. The microwave now works perfectly and for $20 I have it repaired and working again. Well worth the time and money as well as saving the unit that without the repair would be in the trash. Happy Happy Happy. 

Replaced the holder assembly with 3 switches assembly. I am a retired GE appliance dealer. 

Unplugged, removed top/ side of microwave, made sure capacitor de- charged. Took out screws that held switch assembly. Removed bad switch and put new switch in. Also checked old switch when removed with multi meter to see if bad. It was. Put new switch in. Worked great . Reassembled microwave and put back in place. 

Had to replace the whole side bracket that holds the switches, not too hard to do. 

Door switch 

I took the microwave case off and checked each switch after it started turning on when opening the door. One switch had shorted out. The switch board had a couple parts which broke as it seemed to be a bit brittle so I replaced that as well. The microwave is back to normal. 

Take the top vent off by two screws & then one screw on the side & lifted her up and I could see the 3 switches I need to repair. Then unscrewed the housin to the 3 switches. Took the housin out , put the 3 switches in the new housing & put her in & plug them in . And plug the Nucor and she works like new. Highly recommended to deal with these people good people for the do-it-yourselfer. 

I took the cover off. Then removed the door latch assembly from the microwave. I replaced the three switches and reassembled the microwave. the hardest part was getting the switches out of the latch assembly with out breaking the tabs that hold the switches in place. It is easy to break them off TYhey are hard plastic with very little give. 

Ordered a direct replacement and just plugged it in.