A/C vent problem on 1998 Buick LeSabre

I have a '98 Buick LeSabre with an A/C problem. When I turn on the A/C in my car, sometimes the cold air doesn't blow out of the vents. The air is sometimes directed through the defroster. Any ideas on how this can be fixed?

Asked by for the 1998 Buick LeSabre
vac line goes to the back of intake is off
5 answers
Safely rise front right side of the car. Take a look under the car's fender - under fender, front of the tire. Check the VACUUM line leading to the small TANK . If the rubber connection to the tank is broken or leaking, fix it.

You do not have enough under pressure in the system. When idling, air goes to windshield and legs (default setting). With more RPM, more vacuum, your AC works sometimes.
Regards, ZU
I had the same problem-
ended up being the ac vacume silnoid-
you can get part on line for about $75
Vac to the control head or bad control head,
it MAYBE your B C M COTROL MODULE IT CAN BE REPAIRED ,BUT TRY AND FIND A USED ONE AND CHECK FOR A BURNT CURCUIT ON THE BOARD A BAD BCM WILL MAKE YOUR CAR DO CRAZY THINGS OR IT IS THE CLIMATE CONTROL HEAD WHICH I WOULD CHECK FIRST ,U CAN BUY A USED ONE CHEAP PRE TESTED