I just installed a brand new ceiling fan in my sons room in a brand new constructiion home. I followed complete instructions. It has a light and fan. When done it ran fine and was on for over an hour and half. Now all of a sudden the breaker is shorting in the garage. Not sure why it didn't earlier. Let me know

Turn off the breaker, take the fan down. With the breaker OFF, check for any wires that may have been pinched when you installed the fan, any wires blackened from arcing. Also check the fan base for signs of blackening indicating a short. Is there a light kit on the fan? If so, open it up and look there as well. Is this breaker for just the fan or for other outlets, light etc? And by shorting, you mean tripping, correct?

I agree.

Also, what make is the fan?

Is it a GFI/GFCI or arc fault breaker?