air vent controls
 

hey guys i need help bad right now!!! so today i found out the the control knob that controls where the air flow for the air vents goes to (the one that chooses if i want air at my face, feet, both, or defrost) stopped working all of a sudden. it was working fine this morning on my way to work. but then on my way back from work all of a sudden i realized i switched it to defrost but like 2 minutes later i noticed the warm air was still hitting my face! i tried turning the knobs back and forth thinking it would somehow fix it but nothing happened. once i got home i turned the knob back and forth again trying to listen for the sound it makes when its switching directions but i couldn't hear anything. :\

so basically my question here would be what should be the first thing i check? are there any fuses relays or things i should check before considering the motor that controls the air flow is bad or something? i really need to fix this asap because its winter and ice builds up pretty nasty on the windshields! and having the air pointed at my face 24/7 instead of the windshie-d aint gonna help:/

also i dont know if this has anything to do with it but 2 days ago i got a new battery with more cranking amps than the original battery. do you think the extra power might of fried something? i just think its odd how i just got a new battery and all of a sudden my air controls mess up :/ according to the parts store it was a perfect match for my car but it was a more high end battery with a longer warranty i got it cuz it only costed me like 10 extra dollars

More CCA doesn't necessarily hurt you at all. I bought my Cutlass Supreme with a truck battery. That definitely had more CCA than what the car called for.

Those climate controls usually mess up for no logical reason. Happened to me twice in 2 cars. You might have to change it, worst comes to worse but I would try to check the electrical wiring of the climate control and the vacuum lines. If I'm not mistaken, these cars have electromechanical climate controls. Usually the speeds and rear defrost are electrical but the temperature and position are mechanical. I don't have my Grand AM anymore (the Alero's twin) so I can't verify for sure, but these were lower end cars, so they weren't fully electric.

Another thing to check is whether or not the knob is broken from the inside. May sound dumb, but it can happen, although the know may just come off. It's not always the case though so it's something simple to check.

pull the knob off and check the back to make sure the tab didn't break off on the inside. on the 01 and up alero's they have a thin little tab that makes up the flat side of the knob and I have seen it break off on multiple knobs.

the mode switch (face, feet, window) is vacuum controled. if a vacuum line has come off then it would not work. however it would default to defrost. so like 03glgold said, pull the knob off and check it in there.

Ive pulled off the knob and everything is fine i took the whole control apart and everything still looked fine. The only noticable thing i seen was the small electrical contacts inside the control looked a worn out and a bit corroded i cleaned it as best i could but it still doesnt work. And i really dont think the vacuume lines that controls the air flow are the problem because the temperatur control still works and throws out hot and cold air as i choose and they both are connected and work through the same vacume line