a couple months ago i broke the vacuum line under the hood that goes to the air that lets it change from defrost to front vents well i hooked it up today and when i turn on the air it takes like a minute or 2 to change from defrost to vent but then when i get on it it goes back to defrost quick then i let off the gas and it slowly goes back to vent another minute or 2 i checked the vacuum i have it hooked 2 and its got a good vacumm on it any suggestions thanks

 

sounds like you have it hooked up to a ported source instead of a constant source. the line sould be hooked up to the manifold.

 

its coming straight from the manifold

 

Bad,

There should be a vacuum reservoir on your car. It is usually either a plasic ball in a fender with a single vacuum hose connection or a cylinder with a single connection (older cars). If this reservoir has split or otherwise failed, the system will react as you describe. A leak in the vacuum hoses in the car interior can result in a similar problem.