Followed the YouTube video from AppliancePartsPros.com precisely. Took about 40 minutes because I would do a step and then go watch YouTube for the next step. Putting the control panel back was the trickiest. Worked perfectly.
Mine was a 20-year-old Microwave/Oven Combo from KitchenAid. The Microwave Light burned out. Called AppliancePartsPros.com and they gave me the exact part I needed.