Wathen1955

Hi everyone,
The other day when I engaged the AC, the air was directed to the floor vents and the defrost vents. I was finally able to get it to the front vents by selecting the other buttons then back to AUTO. Any idea what causes this? Is this something that I can fix myself? Where do I start?

Note: I haven't worked on cars since owning my 1971 El Camino, so I would need detailed instructions with pics if possible. Thanks
Charlie

pianoguy

Very common with '96 models - here's a good thread on the subject:

http://forums.corvetteforum.com/c4-t...l-problem.html

Also, inspect the vacuum check valve that is toward the back on the passenger side of the engine, under the fuel rail cover. If it is suspect, they only cost a few bucks at Autozone or NAPA.

95BlueBomber

The last time I saw this problem it was the vacuum T under the passenger fuel rail cover.

huddo330

I had exactly the same problem on my 96.
It was the vacuum check valve. Easiest fix I've ever done.!

Wathen1955

Thanks for the info. Where is the vacuum check valve (pic please)? Sorry but I don't have a service manual yet.

toptechx6

Lift up the right side fuel rail cover (black plastic with Corvette logo) it should pull off straight up. You are looking for the plastic valve with three ports, (black and white in these pictures) One or more ports may be broken off, they get brittle with age. If it is broken it should also fix your cruise control as a bonus.





If you can't find one at the local parts store a dealer should carry it under one of these part numbers, for less than $10
14056648 superseded to 15733271

betyelou

RUU

I thought that's where the AUTO setting was supposed to direct the air flow. The fact that you were able to redirect using the other buttons does not indicate a vacuum or controller issue.

Wathen1955

The AUTO button turns on the AC. If you select any other button, the AC is turned off. This really through me for a loop when I first was trying the AC. Normally in other cars with AC, you then would select where you wanted the air directed. This whole thing with the AC and vent buttons is strange to me. If I select the vent button, it takes almost a minute before I feel air coming through the front vents. The same with the AC, but this time, it never came over the front vents. In the past, it would take a minute or so before you would feel any air from the front vents. Just seems strange to me that it works this way. I was pushing the other buttons thinking it might have been stuck some where in between. I'll look for the check values. Thanks for the pictures!