Hello, my Whirlpool sidekick is having temperature issues. It is just over 6 years old. The temperature in the refrigerator is freezing everything. After adjusting the thermastat the temperature turned to luke warm so we turned it back to where we have had it for 6 years and it is freezing everything. We had a tech come look at the refrigerator and suggested a part called SUPCO 3n1 for the "low price" of $350. We didnt have him do it. We later found reviews on the web that the part he suggested was a possible fire hazard. I am pretty handy and can figure out how to install the parts but I am not sure which parts I need. I am pretty sure its not the thermastat based on what the tech said. he did say there are three small parts he would need to replace if he didnt install the Supco 3n1. Can you help me diagnose what parts I need?

Thank you!

Dwhitford1