Refrigerator not freezing/cooling at all, how can i fix it? What part should i replace? appliancerepair

Whirlpool WRT779RFYM10 - 5 years old

So recently my fridge started acting up, i found that food in the fridge compartment was actually freezing. I attributed this to the fact that i had too much food in the freezer, maybe blocking vents or airflow.

So i began to eat stuff from the freezer to get rid of it, and it seemed to be working because a dish of water i put in the refrigerator compartment that was previously frozen solid finally turned to liquid.

But then maybe two days later, i found that the fridge compartment wasn't getting cold, and food in the freezer was actually thawing!

So i threw away all the food in the fridge/freezer and started to do some testing.

It was NOT because the evaporator coils were frozen over, any frost had already thawed. When I first looked at the coils though there was a chunk of ice at the start of the evaporator coil where the thin copper pipe turns into a thick copper pipe as shown here: http://ift.tt/2la09Tb

So i removed that piece of ice and unplugged the fridge and left it for 8 hours, then i plugged it back in overnight. But in the morning i found that the ice tray i left in the freezer wasn't frozen at all, so the freezer wasn't freezing and the fridge wasn't cooling.

I left it plugged in for another 7 hours and when i got back it looked like this: http://ift.tt/2kN6yR3

As you can see, the start of the evaporator coil froze up again, the entire thin copper pipe, the thicker copper pipe, and the beginning of the silver evaporator coil, but stopping right before the first metal fin. Then beyond that, the rest of the evaporator coil is not cold at all.

Anyone know what i can do or replace to fix it? In the back of the freezer I have access to the evaporator coils and there is a temperature sensor attached there, and i have access to the temperature control unit / thermistor in the fridge compartment. And of course access to the compressor area at the back/bottom of the fridge.

++ What I've found so far:

Freezer compartment is NOT freezing.

Refrigerator compartment is NOT getting cold.

Evaporator fan is working fine.

Evaporator coils are not cold (at least when I'm checking right now)

Condenser fan (i think that's what it's called, between the compressor and the drip tray at the back/bottom of the fridge) is working fine.

Condenser coils are not getting warm/hot, at least when I'm checking now, i vacuumed dust as much as I could.

Defrost heater is not on (at least when I'm checking right now)

Capacitor (attached to compressor) I have no idea whether it's fine or not.

Temperature sensor in the freezer I have no idea whether it's fine or not.

Thermistor (in the fridge compartment) I have no idea whether it's fine or not.

Compressor is hot and seems to be working.

Submitted February 19, 2017 at 11:09PM by abedfilms http://ift.tt/2la1R7c appliancerepair