This bracket holds the metal or plastic flapper that closes off the exhaust duct when the fan is not running and opens when the fan turns on. If the exhaust fan on your microwave does not appear to be...
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.
Took a putty knife and our the inside trim molding around the glass loose used a phillips screwdriver to remove old handle and install new handle popped trim piece back on.