How to Troubleshoot & Replace Whirlpool AP6015809 / WPW10151374 Air Diffuser Assembly

Bought a new thermostat and door diffuser. The thermostat was a little different from the original as far as the power connections. Instead of being on tip top of each other they were side by side. After calling customer service found out it doesn't matter how you hook them up. 

Video shows that it takes a hard press to set the retaining clips, however my neighbor and I could not force it in place. I had to file the body of the diffuser to make it work. The refrigerator is now working fine. 

Replaced two parts - Defrost Thermostat and Air Diffuser Assembly. 

Watched video to determine how difficult it would be. Seemed very simple. Just followed the steps on the video. Replaced diffuser with a new one. Also replaced gasket with a universal kit. 

Food started freezing in the frig side. The first thought it might have been dirty coil racks under the frig. They were dirty (if you have an animal in the house make sure you check this periodically) we got a lot of cat hair and dust out. That helped but didn't fix the problem. I felt like it was the thermostat and after a few days investigating and watching the video on APP I decided to buy one. Very simple to order and got it in a few days. Took me about 30-45 minutes to install and Praise the Lord! it fixed the problem. You can check the thermostat with a meter but the old one would hold for a while then get colder and start to freeze. The only thing that is a pain is sliding the protection tube on the temperature sensor rod. I had one question and called Tech the next day they answered it. Now the ole Kenmore is running like a new one. Thanks APP for you help! 

New air diffuser--part arrived quickly and the repair took less than 30 minutes. 

Ordered air defuser as suggested by you and it came the next day ! 

Thanks to AppliancePartsPros.com and their great website, I was not only able to identify the cause of the problem, but I was able to order the part, follow the repair VIDEO and resolve the problem - ALL IN LESS THAN 48 HOURS(!!) from start to finish - and I mean from the time I found your site, ordered AND RECEIVED my part, and completed the repair! Your site/repair video saved me at least $200 on what would have been a repair service call had I not been able to do this myself. I am a 66 year-old woman with NO experience in repairing appliances, but your site made this repair possible and profitable for me! THANK YOU! I am now a dedicated fan of AppliancePartsPros.com