I have a Maytag side by side and the refrigerator isn't cooling. The freezer is cold but has a big icebuildup in the bottom. Also the icemaker is wooring poorly and the spindle thing is frozen in. I checked the fan and it is working. I emptied everything out last night and let it all thaw out. Going to check it later today to see if it works. Any ideas what cause the fridge not to cool or the icebuilup in the freezer?

The defrost timer switch is the culprit here. You need a new one if you don't want to keep defrosting the machine every other day.

Where is the defrost located?

Where is the defrost timer switch located located?

The switch is probably in the computer motherboard (if your machine is newer) for the fridge and needs to be professionally replaced. If you don't know where to find it, better to have a professional get the part and install it for you. Be sure you are home at the time and watch the repairdude very carefully so you can replace it the next time your fridge does this. The defrost timer switch is usually the first thing to go in a side by side. I had to replace one in my side by side twice. Now I gave up side by sides and have an old fashioned top and bottom kind.

Look for defrost timer, probably be a black box about 2" square, have 2-4 wires to it and be held in place with two small screws. You will know it when you see it. It will have a hole in center of box in which will be the end of a shaft. Shaft will have a slot for screwdriver. Slot will be such that you can only turn it clockwise. Turn about 1/4 turn. Should feel clicking. If this temporarily solves problem, replace defrost timer. Available at most appliance parts stores. Defrost timer most likely in compressor compartment but can be anywhere. Some models in the past have combined with ice maker motor. Try to obtain wiring schematic for you model.

Freezer side runs all the time