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HVAC Issue. Cant switch between any of the vents for heat

J

JohnnyV

New member
Hey guys,

So starting today i cant switch between all the vents in the car (1999 GTP). I tried turning the heat on and off about 8 times but that did nothing. It still sounds like its blowing strong and still nice and warm, i just cant switch it between defrost or the floor or even the dashboard vents.

What could be the issue here?
 


theres a vac line on the top of the super charger, it leads to the fire wall then down the fender to the fuse box where it them joins a loom of wires and enters the cab of the car. check this line for cracks or leaks. it powers the vent directions.
 


So more than likely i still have a vacuum issue? il have to get a mechanic to look at it then.

Is there anything else i should test to make sure its a vacuum issue? like cruise control?
 
you can check that your self easy. if that line is cracked the vents wont change direction.

or the climate control head unit in the dash took a dump.

the vac line is a free check, and would cost less then a buck to fix most of the time.
 
Is it common for the control head unit to go for a ****? cause that line to my eyes looked fine.... but im a computer guy... not a car guy, lol

Edit: I'll turn the car on and see if i can hear any leaks. Should i turn the heating system on and then listen? or should i hear a vacuum leak without the heating system on?
 
that line under the hood runs to a box behind the dash then to the vac pumps that move the vent controls levers. so you may hear a hiss under the dash if one of the inside car line broke, or the vac pump its self.

ive seen on the board here where the unit does go bad, then others who changed it and still didnt get it to work.


these levers are plastic under the dash, they break all by themselves sometimes. so if you open up the dash some you can see if the vac pumps are moving, if they are the lever arms snapped.

this how to is for the blend door actuators, but the vac pumps are right there next to them, its the round part in the lower right of the first pic. theres one on the pass side as well, removing the glove box door gives you full view of that side.

http://www.grandprixforums.net/showthread.php?t=21941&highlight=change+blend+door+actuators
 
So now its working again.... I drove home from work and it was working no problem. I even stopped and restarted the car again as a test and it was fine. What could be going on then?
 


Well I'll keep an eye on it I guess. I do have a different issue though. Every now and then my air bag light comes on for up to 5 min (sometimes less) then goes away. Started at about the same time as my vent select issue.
 
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