We own a built-in Jenn-Air (Whirlpool) microwave oven. When the oven light burned out I was left baffled as to how to replace it; there was no obvious way to access the bulb. After a bit of Internet sleuthing I found out that I would have to uninstall and disconnect the oven from the cabinet and partially disassemble the oven's housing. I also found out that it required a special bulb, available only from certain suppliers. Luckily Appliance Parts Pros stocked the bulb and provided the information necessary to replace it. The bulb arrived promptly and a few days later I uninstalled the oven and replaced the bulb. While most handy people can do this, have a helper available to unplug the oven as you pull it out of the cabinet and possibly to help carry the oven to a work surface. The only necessary tools are a normal #2 phillips head screwdriver and a stubby one. If you don't have a stubby screwdriver, that's OK- you'll just need to take off the top of the oven enclosure too. The rest is just disassembly and reassembly. Be careful because there are two screws that have different threading from the others. Make a note of them and where they came from so you can put them back in the correct holes!
That's it!