Grease filters are only used in over-the-range microwaves that recirculate air. Countertop microwaves do not have grease filters.
If there is an odor coming out of the air vents, you'll need to clean the inside of the microwave because that is where the smell is coming from. You might have some burned food or specs of food on the inside walls of the microwave or under the turn table that is causing this smell. If you burned something like popcorn in the microwave, the smell can linger.
Here are some different ways you can clean the inside of your microwave: whirlpool.com/blog/kitchen/how-to-get-burnt-smell-out-of-microwave.html
Make sure you don't have anything under/near the microwave itself that could be blocking the vents. I would suggest putting an open box of baking soda in the microwave overnight if the odor lingers after cleaning the interior.
To access the light bulb would require removing the outer cabinet.
NOTE: Microwaves are inherently dangerous to service. Internal capacitors can retain a lethal electrical charge even when the microwave is unplugged, so I wouldn't advise you to change the bulb in most cases. However, your model uses an inverter instead of a capacitor, but you should still unplug the microwave and be careful, if you decide to change the bulb.
The interior light of a microwave should not be replaced with an LED light, as the interior light should always be a glass incandescent bulb. All microwave light bulbs that are the same wattage are approximately the same brightness.
The reason why you won't see any parts listed for newer countertop microwaves on www.SearsPartsDirect.com
is because all newer countertop microwaves (from all brands) are made in China and are not cost effective to repair. This why you see a notice that "No service is available" for countertop microwaves. For repair of all other appliances, you can call Sears Home Services at 1-800-4-MY-HOME.
For most other products, you can find parts, diagrams, and your owners manual on www.SearsPartsDirect.com
, just enter your full model number. (ManageMyLife.com was the prior version of www.SearsPartsDirect.com
Here's your owners manual: searspartsdirect.com/model/3fqyroim2x-000582/kenmore-20479393610-countertop-microwave-parts
Hope this helps!