Julie F Mayfield , KY December 05, 2014 Appliance: Frigidaire Refrigerator FRT21LR7AB4 Frigidaire Refrigerator Frt21lr7ab4: Broken light switch. How to replace Light Switch. I purchased and used the part that was recommended by the appliance pro through chat. It was super easy and the part was shipped super fast. Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes