GM8131XEQ1 - Instructions

Remove top grille (2 screws), undo control panel (1 screw). Tilt down control panel, switches are on the left. There are actually three switches that are involved with the door, two horizontally mounted, one vertically mounted. This would be an EASY REPAIR, but it took me a while to figure out which of the three switches was bad, and also took a while to figure out that there is a plastic rod that inserts through the hole in the switch body. Once i figured this out went like a breeze. Lower horizontal switch was the bad one, but since the kit came with two switches i went ahead and replaced the upper horizontal one as well. IT appears that the horizontal switches are probably more likely to fail than the vertical switch based on the position of the switch and force angles. Works great now!

1. removed vent across the top to gain excess to Screw holding control in place. 2. Removed control panel to access Fuse. 3. Remover fuse after pulling plug. 4.Tested fuse for continuity with volt ohm meter noting no continuity.5. Orderd new fuse. 6. receeived new fuse and installed infuse holder.7. plugged microwave plug back in receptical and tested unit now working OK.Reversed steps 2 & 1 job complete

Unplug the unit before servicing. Need phillips screwdriver. Open door. Use step ladder to access and remove 2 small screws from top of the room air diffuser at top of unit. Slide diffuser slightly to the left to align the diffuser's plastic tab on the left side to rotate toward you. (The wires for the front control panel are at the far left side of this difuser, but difuser is slotted for easy removal). Once the difuser is removed you will see 1 screw at the top that secures the pannel cover on the left side of the unit. Remove screw and slide this panel slightly up and out. This exposes the plastic frame that holds the upper and lower door switches. To locate the door switches and observe how they work, close and open the door and watch the door (bayonets) open and close the micro switches. Do the (red) buttons on top of the switches move up and down when the door bayonets push and release? If the buttons do not "pop" up when opened the switch is defective. The switch frame is secured with 2 screws. Remove screws and rotate the unit out for easy access to the micro switch(s). The internal (spring?) on my unit that is suposed to allow the red (visible) button on top of the switch to "pop" up when the door is opened was broken. Carefully pry the switch outward while being careful to lift the plastic holder-piece that holds the switch in place. Be careful, there is a small pin on the frame, so rotate the switch OUT toward you while lifting (carefully) the plastic holder-piece (you will see it on top of the switch). You can use an ohm meter to test the continuity of the switches. But if the buttons don't "pop" they are defective. Replace switch and reassemble.

I removed the unit from the wall. Took the cover off. Set the unit on its side. It revealed the working parts. Removed the old micro switches. Put in the new oness. Presto, it worked. Very easy for me.
The parts was delivered almost before my notice they were shipped.

Problem would come and go. Found service schematic inside unit. Perform all the suggested tests. One possible solution was the primary interlock switch shown on the schematic and a check found the switch stuck. It would free up some times but would stick again in the open position. Ordered switch which was a simple plug in unit.

1. Removed cabinet screws (10-15?). 2. Removed cabinet. 3. Removed top interlock switch which actually was not defective. The press clip connection appeared as if it had been arcing for quite some time and the corrosion created resistance sufficient to prevent the current from getting through the switch. 4. Replaced switch anyway but broke plastic retaining clip despite every effort not to do so. Reset broken clip with super glue. 5. Reassembled cabinet and appliance is in good working condition.

Watched a couple of repair videos on Youtube by searching for the model number. Found out what to do in order not to get shocked by the powerful capacitor.
Ordered the two switches (To be sure, I could have ordered a third switch as suggested in the videos.)
Bought a tamper-proof star bit to get the cover off. Followed the directions to replace the switches. - I broke the harness and had to use some super glue, but it's all good. I should have removed the harness instead of trying to get a switch out while it was still in place.
It's all back together, and the wife is happy!!

Removed some cosmetic panels. Removed the assembly with micro switches. Examined the faulty switch by checking the clicking action of switch. Two others were ok by this method. Replaced the switch with new one. Works fine so far. Thanks to web site and YouTube videos.

Watched a you tube video prior to installing new switch. Followed the video which gave me confidence i was up to the task. After removing the touch pad I found my design was not exactly like the you tube model but I found the defective switch, replaced it and put the microwave back together. Works great. Again watch the videos

I looked up my problem on the internet and found a very helpful video. Microwave on video was different brand but the internals and methods were very much the same. The video made it simple and easy to fix. Found the replacement switch on the LG parts site and ordered. Two different switch types. One with red switch, the other green. Part was $7.28. Saved a bundle in service costs. Here is the repair video.

https://www.youtube.com/watch?reload=9&v=_AglBJoHgDs

I went to LG website enter model number and was given a list of parts that need to be replaced with a percentage of which part fails the most. I order micro switch PS3522738 which arrived and PS3529293 was backordered. I installed the one that arrived. The microwave worked briefly. I reordered and waited for both switches to arrive and installed both. The microwave still doesn't work.

Take cover off microwave. Check door switches to determine which one was faulty.Remove and replace faulty switch.

Easy, and the microwave still doesn't work.

i unplugged the unit,unscrewed the outer shell so that all the wiring and internal components were visible.starting at the first of three micro switches i removed the slip on terminals installed the alligator clips too the wires so the switch would now be bypassed.i made sure the wires and clips were not touching anything plugged unit in and it worked.i then installed the new switch and closed up the outer shell

Initial failure of over range microwave Aug 3rd. Control Panel worked but no heat. Took to local LG authoriaed local repair place. They fixed it quickly and we re-installed it. Worked fine for 2 months then had similar failure again. Agaim took to same authorized repairer. They kept unit for 3 months but finally concluded theu could not fix it and suggested we contact LG for a partial refund. When they tested the unit during re-assembly in my presence, there was a blue flash and the fuse blew. Since we had built a custom tile mural back splash around this unit, I brought it home, ordered a number of time delay fuses new capacitor and two new high voltage diodes. However, using my Fluke DMM, I checked the existing capacitor and high voltage diode and they checked OK so I just replaced the time delay fuse. The high voltage transformer leads had 2 possible ways to connect to capacitor and diode. Tried one way, plugged unit in and turned it on, and immediatly blew the fuse. Replaced the fuse and reversed the high voltage transformer connections,amd turned unit pn, and it worked perfectly. Since we had experienced several power failures during the time of the original failure, the repairer concluded that power spikes might be at fault, so I also purchased a TrippLite ISOBAR4ULTRA 3300 Joule surge protector between wall outlet and microwave, and re-installed over range. It has worked perfectly since.