I know I've seen this addressed, but I'll be darned if I can find it.

My AC blows strong and cold. Only problem is it really just blows out of the foot wells and very little to none out of the dash vents.

If I recall, there is some sort of a valve/T deal that needs replaced????

Any help is GREATLY appreciated.

 

Here's the thread:

http://forums.corvetteforum.com/show...post1551538886

There is a valve under the passenger fuel rail cover. Easy way to test it is with the car running, just pull one of the lines coming out of it and see if there's a vacuum, then replace it and pull the other line off and check that one. You're lucky if that's your problem.

I just fixed my '96 with the same exact problem not even two months ago. Please feel free to email me vsavaglio@yahoo.com if you need any help with it or have any questions about the info in that thread.

Vinnie

 

Thanks Vinnie! I'll give that a look tonight.

 

Oops, I just read what I wrote and it doesn't make sense. I meant I had the same problem with the defrost and floor vents. Unfortunately my problem was not that 3 way valve. If the valve is good, then the next thing to check is the box under the dash. Just turn on the car, don't start it, and with the radio off start hitting the different vent buttons. You should hear faint "clicks" from under the dash near the pedals and steering column. Anyway, I'm getting ahead of myself, good luck!

Vinnie

 

For some reason, the A/C out of the foot wells blow a ton harder than the vents on my 89. Is the 89 different from the others???? I'd like the opposite to have happen. My former Honda never had A/C in the footwells so I'd like the A/C to blow hard out of the dash vents and not the foot well. Now I'm starting to see all of my tiny intermittent problems from the left headlight motor spinning to the up and down function not working on my power mirror, to my windows and doors not being aligned properly to seal out the rain. But that's off this topic.....

 

Umm, I actually don't know how the 89 is for the HVAC, I've heard that '96 is different from all the other years, but I don't know for sure.

 

Well, I have the clicking sound from each vent option.

So, I went to check the vacuum on the 3-way valve. I must have a bad vacuum gauge as I couldn't get a vacuum reading from either line, so I pulled the one directly off the intake and tried there, still no vacuum reading-not even a blip. Even if there was a massive leak, I'd get something from the intake.

 

That's a really good sign then, it usually means the programmer is working and it's probably a vacuum issue. You probably don't even need to use a vacuum guage. All I would do is with the motor running, just pull the two lines coming out of the t-valve, one at a time. You should hear the vacuum pretty clearly coming from the valve (if it's still good). Good luck...

Vinnie

 

In that case, I heard vacuum out of both openings when done one at a time, loud and clear. Still no air out of upper vents. Could the hoses between the t-valve and the programmer be blocked somewhere?

 

It's possible. But it's more likely there's a problem with the vacuum line connector to the programmer under the dash. There's a block connector for all the vacuum lines. The programmer has these rubber nipples that fit in this connector. It's possible the connector is lose, so you're losing vacuum that way. Or, as in my case, one of the rubber nipples was damaged, blocking the vacuum line, I just cut the damaged part off, good as new. I'd crawl up under the dash and see if that connector is loose, if it's not, then just pull the box out and take a look.

 

Sounds good, but where is the box?

 

That's the fun part. It's under the dash on the firewall right above the brake and gas pedals. The programmer is just a relatively small black box with a wiring harness on top and the vacuum connector on the front of it.

Vinnie

 

All of the C4's flow a small amount of air to the floor to keep it cool. This design came about after numerous complaints that the Vette's exhaust system made the floor too hot. If the flow is stronger at the floor than at the vents there are a number of possibilities: the Programmer (Electronic Air above the accelerator for '89) may be leaking or the Control Panel and it's vacuum harness (Manual Air) may have a defect, or the foam that seals the duct work may have deterioated and the air flow is escaping into the dash. I'd start by removing the passenger's side hush panel and checking for air. If it's flowing around the ECM and not out of the vents, the duct work needs to be sealed back up. Remove the top panel for easier access and at the same time, make sure the defroster duct work is sealed up tight too.

If the duct work checks out, check for vacuum at the solenoids which are mounted on the left side of the heater plenum. With the a/c on, the only solenoid that should have vacuum is defrost. It's vacuum hoses are tan and red. The a/c solenoid hose is blue and the heater is pink. Neither should have any vacuum. If the a/c solenoid has vacuum, disconnect to see if flow improves. If it does, the Programmer (Electronic Air) is bad or it's the Dash Controls (Manual).