My Maytag Wide by side refrigerator will not get cold. Yesterday the milk didn't seem very cold. Today I turned it up as cold as it will go, and still it seems pretty warm. Any suggestions?

First of all that is the wrong thing to do is to turn it all the way up you need to look at a couple of things you need to check to see if the fan in the back of fridge is working and the compressor if it appears to be filthy clean underneath the coils fan etc. then check to see in the front of fridge if there is airflow should be warm air then open fridge and on the left side there should be a vent and it should be blowing cold air if not post back with the results.

After you have checked the back of the unit as JCosta said check for ice buildup on the back of the freezer wall. If there is on the back wall you have a defrost problem. If you are not handy call for help. If you are handy take the cover from the top of the refrigerator section. Two finger holes are in the back pull them down BEFORE you pull the cover forward. Remove the 2 hex screws and 2 Philips screws that hold the second plastic piece in place. On the right side as you face the unit there is a small white box that contains the defrost control. This is an intelligent control and not a timer(bad choice). Unplug the timer and jump between the terminal to the defrost heater and power. (Look inside of the timer and you can see the markings on the board) If this makes it defrost you know that your heating element is good. While it is defrosting you can look into the holes in the bottom-back of the freezer and see them glowing orange. If they are you probably need a defrost control. Good luck