Please bare with me. I am trying to find the problem myself and this is my first time working on a fridge. My freezer is working fine but the fridge part is not cooling right. It's not cool enough. So right now I pulled everything out and unplugged the fridge completely. I took off the back panel because I noticed frost buildup. The coils are covered so it's manually defrosting with the doors open. I can't find the defrost timer anywhere. I am trying to find out what is causing it. I did noticed the thermostat is completely covered with frost. I am not sure if it matters or not so if it does please let me know. I have read that I need to check the timer first and see if that works before checking the defrost heater and thermostat. I appreciate any and all help.