Doug O Lexington , MI February 12, 2019 Appliance: Frigidaire Refrigerator FRT21S6JQ4 Frigidaire Refrigerator Frt21s6jq4: The refrigerator compressor would not run at times. How to replace Defrost Timer. I replaced the compressor start up relay and so far it has been working. I know it has only been 3 days but so far so good. I would like to compliment the woman I spoke with on the phone she was very professional and helpful. 3 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes