Air conditioning problem on 99 Chev. Astro



Recently my air conditioner began to blow only through the defroster vents on top the dash and at side windows. It is still cold and the blower works fine, It appears the vent directional controls are not working, What to do?


Check for a vacuum leak.


Thanks for the response: Where would I look for the vacuum leak, under the dash somewhere, in the engine compartment, in the black air conditioner box on the left side of the engine compartment??


Many cars have HVAC air flow controlled by vacuum motors. The vacuum is supplied by the engine. There will be a line from the intake manifold to a reservoir for the HVAC system. This reservoir is typically on the firewall, but could be elsewhere. There should be a check valve between the engine and reservoir so when you have the accel pedal down, you don?t lose vacuum. The leak could be anywhere in the system, lines, valves, vacuum motors. Checking under the hood is easy. Checking in the dash is harder so check under the hood first.


Thanks for the info. I will do a follow up on this to see if I can find the leak.