---MIKE--- wrote:
The temperature in my Whirlpool fridge (a little over
one year old) is staying at 48 degrees while the freezer stays
between 0 and 5 below.

There you go; the freezer is working fine, it just isn't maintaining the
fridge. You either have an air leak in the door gasket, ice buildup in the
duct between the evaporator coil and the fridge, or another blockage in
same.

This all assumes that you have the air control (if equipped) set to the
correct setting. Try moving it to the other extreme to see if the fridge
gets cooler and the freezer warms up.

Jon