madmatt9471

My Vents do not cycle as they should from floor to Defroster but at all times and "ALL" vents have air blowing out!

The AC works perfect and it is "COLD" but when I want it to cycle to the middle to blow COLD air right into my face - No matter which position the mode button is in on the HVAC Climate Control - it still blows through every vent!

Do I have the dreaded Vacuum line battery acid leak onto it and it needs to be replaced?

If so can someone shoot me the link and directions on the path of the Vacuum line in question and everything to look for along the way

Any and all help will be appreciated!

I do not need any info on the ACTUATORS They are fine

Thanks,Matt

bestvettever

Hi copy of my post where you originally asked the question
HI, The most likely culprit would be either a vacuum leak, or disconnected vacuum line, or the control head is bad.
Check the main vacuum line coming off the intake manifold, through the harness, and ending at the vacuum tank on the pass side hinge pillar under the battery box by the wheel well, it then goes into the cabin to the vacuum junction block and to the control head, look for a break or not connected to the intake manifold. Could be Battery Acid damage below the battery box where the lines run. If all is well with the vacum lines, it is most likely the control head.
Good Luck
Edit, the line starts at the back of the intake manifold.

madmatt9471

Sounds good

I will go after it and post my results as well as some pics for others to follow

Thanks for the heads up! I know the line from the back is good but under the battery I'm not too sure

Had the motor out for the forged one and the line was good - But I might just replace it all the way just to be sure

I must document this and do so with pics
Thanks,Matt

c5mtl

I SUFFERED with this problem for a year....pulled intake off 2 times looking to find a vacumm leak.....first problem turned out to be my installer didnt bother connecting the vacumm line to my fast intake.....so pretty simple conected it and i was done.....(at least that what i thought)....got into my car and started messing with my vent and nothing happen still no control of the flow.....then i thought it was my controller....so i ordered antother one from fleebay.....ending up paying $100 for a used controller that doesnt even light up.....plug it it and same problem ...no control....then i checked for acid under the batt....all the lines are clean...then i check the check valve in the vacumm canister...all ok..finally a couple of weeks ago i pull the intake to tighten a ground bolt.....decided to check the intake vacum line again but this time i blew some air through it and felt a huge leak about 8 inchs below the intake...somehow the vacum tube touched the head or block and melted......bypassed it with new tube.....AND IT WAS FIXED.....Save youself some trouble and blow some air into it and check for leaks in the line
good luck

madmatt9471

Yeah!

I was going to do it that way or do a SUCTION test with my mighty vac on the line in question

I will find it and again will document for everyones benefit I will have to do this after the Vette show tomorrow and on into sunday but I will keep all posted as to progress

Thanks,Matt

madmatt9471

Tired from the Vette show!

I will do it tomorrow

Thanks,Matt

madmatt9471

Well here it is the write up with pics:The Link
http://forums.corvetteforum.com/show....php?t=2077593

It's all fixed

Thanks,Matt

bestvettever

Hi, glad it worked out for you, and thanks for sharing the fix with the rest of the forum.
Luck To ALL