I have a central AC unit and inside my house its running fine so I went out side and the outside unit was running also but it was blowing cool air not warm. Then I checked the coolant line from the outside unit to the building and it is not getting cold at all?

It sounds like you are low on freon. Call service company

If you r low on freon, chances are the cool line will be frozen solid, need to shut down the unit and let it defrost, also check the braker to the outside unit, sometimes it trips and can't tell because of the double breaker, if that is not the problem check the starting capacitor, or get it kick started.

The fans can be on inside and out but if the compressor is not running it won't cool,get the compressor to work and check the freon..