thanks for the help . could you be more descriptive of where this "tank " is under the car. Not much on finding things on this car thanks again

thank you , and for the heat it does the same thing .. i'm guessing the vacuum hoses because i had a astro van once that did the same thing but to find out for sure i need a diagram to trace down the leak if this is the problem.. if you have one please reply &post it here thanks

can a hole in the vacuum hose cause the air to blow out the side vents and not the middle ones?

I have an 89/ 780 bertone volvo and the a.c. has been fine till today
the a.c.was blowing fine then it stoped blowing through the middle vents and now only blows though the side vents by the door . its blowing cold but just from the side vents . Is this a vacuum hose or what and if it is do you ...