Second Floor Bedroom Little HVAC
First, Take a probe type thermometer and check the temperature drop across the cooling coil. The temperature drop should be 15-20 degrees F., and preferably closer to the 15 degree temp. Next, check to see how many return registers are located in the basement. They should be located near the floor. Remember that multi-story houses like yours all have similar problems since cold air is heavier than warm air and tends to fall to the lowest areas. Look to see if every room has it's own supply pipe and not have a common pipe supplying a lower and a higher room. Count the number of supply and return registers on each floor. Every room should have at least one of each unless this is a newer house, then any thing is possible. The returns for the top floor should have returns located near the ceiling to take the hot air off the ceiling. Measure the sizes of the supply and return ducts include the duct that drops down to the furnace. Also list the model and serial number of the furnace or air handler and the size of your house and it's location, type of windows etc. The more info provided the better. (There are a lot of smart guys that monitor this site that can provide possible solutions if given enough information). Hope this helps