it still blows cold but not thru vents
my a/c does not blow out from the vents it seems as if it comes out from top of on 2007 Chevrolet Express 2500
Most likely your Actuator Door or Actuator is out. The actuator is the most common problem. If you hear a constant clicking noise when adjusting the vent control then the actuator is the most likely culprit. If the control does not click but you are able to switch from floor to defrost, then the vacuum line or actuator door is most likely the culprit.
actuator door is bad and deflecting air to defrost mode.