Refrigerator not cool

I don't know this particular frig, but evidently the defroster doesn't work. Frost buildup has blocked the flow of cold air.

There is a defrost timer, under the frig, accessible from the front. You can turn it with a screw driver. Turn it till you hear a click. If the timer hasn't been turning, that should turn on the defroster, a heating element nested among the freezer coils. Wait half an hour and if it is defrosting, water should be dripping into the drip pan underneath the frig. If so, then replace the defrost timer and you're good to go.

If that doesn't make it defrost, then the problem is probably the defrost thermostat, in with the freezer coils. When the frig defrosts, the defrost heater stays on until the defrost thermostat gets warm. It should be open circuit while warm. But if it is open circuit while cold, it is bad and is the cause of your defrost problem.

If you open up the freezer coils, use a hair dryer to defrost. That is safer than hot water.

Hope you can fix it.