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HEATER/AC VENT DUCTING PROBLEM

 
VETOFF
I love my Chevy Chevette!
Posts: 4
Joined: 10/07
Posted: 10/25/07 07:31 PM

1993 VET with LT1:  My heater and ac work fine but will not discharge air through the center dash vents.  The air discharges through the windshield defrost vent regardless of the setting.  Does anyone have experience with this problem?  Is the problem with the heater/AC programmer?  Any help would be appreciated.  

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phil5129
I love my Chevy Chevette!
Posts: 7
Joined: 10/07
Posted: 10/26/07 03:29 AM

I would check the vent doors controls under the dash. they should be vacuum controled , if so make sure you have vacuum to them and the main control. also make sure the doors are working.  

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Viscount
V-6 Camaros rule!
Posts: 62
Joined: 10/06
Posted: 10/27/07 08:40 AM

Believe they call that the "default" poition. Look under the pass/side fuel rail for for a vacumn tee that may be deteriorated.  

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VETOFF
I love my Chevy Chevette!
Posts: 4
Joined: 10/07
Posted: 10/27/07 07:57 PM

I am having trouble figuring out the vacuum hose routing with the Vin P engine.  I have a loose end of 15 inch vacuum hose coming off a T-connection on the left hand side of the engine that I can't figure out where it goes.  One end of the T goes to the cruise control servo.  Another end of the T goes to inside a conduit and runs back to the vacuum tank.  I can not locate what the 3rd end of T connects to.  Page 9B-3 (Fig. 1) of the service manual shows the routing but is unclear regarding the 3rd T run.  Can someone help?  

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Viscount
V-6 Camaros rule!
Posts: 62
Joined: 10/06
Posted: 10/28/07 01:24 PM

Vetoff,

Go to the pass/side & remove the fuel rail cover. There is a vacumn valve under the cover that may be the problem? Confused  

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VETOFF
I love my Chevy Chevette!
Posts: 4
Joined: 10/07
Posted: 10/28/07 10:10 PM

Viscount,

Thank you for the information.  I did locate the valve and will replace it tomorrow.  Hopefully, this will solve my the issue with the air blowing through the center vents. Laugh

While dealing with this issue, I located a 15 inch vaccum hose coming off a T-splitter on the driver's side that is disconnected.  I am having trouble locating where it is supposed to be connected.  Confused  

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Viscount
V-6 Camaros rule!
Posts: 62
Joined: 10/06
Posted: 10/29/07 08:01 AM

Are you the original owner or did you recently buy the car?


Just a guess, but maybe an updated opti-spark was installed . This usually requires a venting system that is similiar to the 95/96 versions.

That could explain the hose as it's connected on the driver's side with the update. Other than that am at a loss?

Is there, by any chance, a vacumn line in the intake between the MAF & the throttle body? Also necessary on the updated opti?  

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VETOFF
I love my Chevy Chevette!
Posts: 4
Joined: 10/07
Posted: 10/29/07 01:06 PM

I finally located the heater/ac check valve and replaced it as several members on this forum suggested.  Voila!  Problem solved.  For $3.50 and the help of several members, a problem that has driven me crazy for over 2 years is now solved.

The disconnected vacuum line on the drivers side is a completely separate issue and is related to my cruise control.  I can live without the cruise not working.

I am the original owner.  I had a leaky water pump and you guess it, they had to replace the opti-spark as well.  However, I don't believe that they changed any of the vacuum routing.  The service manual shows a vacuum line on the drivers side between the vacuum tank , cruise control servo, and source.  I can not locate the source connection.

Anyway, thanks for helping me resolve the venting problem! Laugh  

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rpj707jr
I love my Chevy Chevette!
Posts: 3
Joined: 12/07
Posted: 12/07/07 12:33 PM

I had the same problem and know one was able to help, so I went to the dealership. The probelm was the AC vacum actuator programmer $1084.38 was the cost of the programmer and $395.52 for the labor. A big hole in my pocket but it works great now!!! I don't think I would have paid for the replacement if it wasn't for the car only has 29,000 on it.  

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