hey guys, 97 monte and this is my wierd problem. starting today for some reason when i accelerate my ac stops blowing air through the vents and goes to the floor and when i left off the gas it goes back to the dash vents. easy acceleration, hard acceleration any acceleration at all and it does this. no prior problems tho right b4 this started today it took a good 2 minutes after i put it to ac to finally start blowing through the dash vents. anybody have a clue as to whats going on here?

 

maybe the dirverter that guides the air flow is loose?

 

most likley you have avacume leak .
Now it could be the switch valve (for lack of a better word) .Or it could be just a hsoe that is cracked under there some where.

the way to find it is to pull th eHVAC controlls out of the dash so you can hear and see them turn the car on and the AC and see if you cna figure out where it is leaking etc....

Good Luck

 

Its definately a vaccuum leak. My old F150 had the same problem. When on max A/C and you accelerated, it would switch to defrost. One of the vacuum hoses had a big hole in it. Pull your a/c controls out of the dash but dont disconnect anything. Turn the car on and put the a/c on and pull the lines one at a time until the same problem happens. Then follow that hose and see if its disconnected somewhere or has a leak. You should be able to find vacuum hose in any autoparts store or you could make a patch with a slightly larger piece of hose that the vacuum hose can slide into and fit securly. Just cut the hose in two at the leak and put the new piece of hose over them to connect them. Maybe rap a little duct tape around it to make sure it doesnt leak or come off.