LinearX

Mark, did they take the intake off of your car when doing the cam? The line that goes into the back of the intake is short and hard. When we did mine, I was able to pull the 90 degree boot off of the intake, but some people have difficulty with that and pull the line and leave the 90 connected to the intake.

Just wanted you to know that you could potentially feel the 90 connected to the intake, but not have the vacuum line connected to that 90 going to the back of the intake.

VIPERBLUELX

I just fixed it. I removed the access panel in the inner fender and found a broken hard plastic vacuum line but couldn't figure out where it connected to. I had to remove the battery and battery tray and unwrap all the electrical harnesses and it was the line that comes off the back of the intake, it was broken completey inside the harness. I have no idea how, but i fixed it and decided to trace the others and found a place rubbed through the line that goes into the firewall where it had been touching the harness beside it. I repaired it and fired it up and the A/C blows like a hurricane. Judging by the amount of dust that came out of the vents when i put it on high I'm gonna say this has been an issue for quite a while.

Thanks to EVERYONE that contributed to this thread.

Mark

Blue LS1-LT1

My '99's problem is not related to A/C and cold air.

My issue is a perceived relative lack of (heated) air flow from the floor vents compared to the dash and defroster vents

Is it normal to not have much air flow from the floor vents compared to the dash or defroster vents?

The fan is blowing hard on maximum, but, compared to the dash or defroster, much less air is flowing out from under the floor vents.

When I switch to bi-level, or just the dash vents, it blows like crazy.

I have the automatic dual climate control option.

Is this a normal condition, or could it be related to a lack of vacuum or actuator problem?

I checked for codes. The DIC display reads "HVAC no codes".

I've owned the car for nearly 10 years, but, until recently, didn't drive it much during cold winter months.

Any help would be greatly appreciated.

tstar

Pin 16 is the illumination wire that controls the lights and their brightness. You can benchtest the HVAC by applying a ground on pin 1 and car voltge on 5, 12 and 16.

Alex99

I have the same problem and am not sure what the reason is. Any feedback on this is appreciated.

enigma94

Back from the dead!

Can somebody confirm that the 'Mode" uses vacuum to change on all C5s? I am having the same as the OP and so I followed Bills post and removed the panel on the passenger side fenderwell and I didnt see the big vacuum box as shown on the first pic in post 17. But I did however find a vacuum hard line like those pictured that was broken.

So I decided to head to the dealer to see how much they would charge to replace this line, and after 30min of going through diagrams and everything the tech said he wasnt sure if the 02's(my year) were ran off vacuum or electrical and that he wasnt sure what the line I had found went to but that they would need to actually pull the car in and look at it before he could give me an estimate on how much the cost would be to replace the line.

I want to make sure first off that the Mode does use vacuum to change the vents on my year (02 z06) and figure out why I dont have the vacuum box in my fender access before I jump into paying the $106 dollar diagnostic fee for the dealer to look at it, or decide to fix it myself.

Bill Curlee

HOLY CHRIST!!! If your dealer doesn't know C5 use vacuum to control the mode damper doors,,,,,RUN FOREST,,,,Run as fast as you can to find a more competent service center!!!

Thats sad! Well, maybe not. They know how to rip $$$106 out of your wallet!

YES,,,,,you have a vacuum issue. That vacuum reservoir is in the fender well all the way at the bottom against the fire wall. You have a leak between the manifold and the vacuum tank. All you need to do is find the leak. Start where the vacuum line enters the main wiring harness near the back of the engine and take the tape off the wiring harness and fish out the vacuum line. Its a tedious job but very doable. Unless you have money flowing out of your wallet,,,you better look at getting your hands dirty.

lucky131969

enigma94

Hahaha, yea thats kinda what I thought. But since I didnt find the vaccume block in the fender access I wasnt sure. There has been corrosion from the old batter all down underneath the tray and I cleaned it up as much as I could but I think that could be why the line is broke. I'll swing by the dealer today and pick up some of the hardline and tear it all out tomorrow and replace the line myself. As i'm not keen on spending 106 dollars or whatever they would charge me to replace the line I pretty much know how to do myself. Thanks for the clarification bill!

BTW, i'll probably snap some pics and try and do a write up on this if I can, as it seems to be a pretty common issue with where they routed the harness under the battery

meloyello

the photos were a great help, but I did not find a vacuum cannister as described, but I did find a selanoid with 2 hoses and a 2 wire harness connected that was broke. Are both of the hoses supposed to have vacuum

bill mcdonald

I dont know if you are still messing with this. I just pulled my access panel out and saw nothing as well.

I had to pull the fender. the tank and lines are right by the door hinge behind the fender. And yes both those lines need vacuum.

bestvettever

That Solenoid and hoses and electrical connector service the AIR system. Secondary Air Injection .

scubaman15

I'm a brand new C5 owner "99 FRC With 25000 miles " I love this car !!!!!!! I want to thank all who contrubute to this invaluable resorce !!!!:thu mbs:
I'm having the dreaded HVAC problems and because of this info I'm going to see if I can find and repair this problem ...hears a link to my E-bay find ...Thanks all of you !!!! http://cgi.ebay.com/ebaymotors/ws/eB...NA:MOTORS:1123

madmatt9471

Beautiful Vette you got!

Here is another write -up with Pictures and full instructions I did here on the Forum, it'll be helpful in conjuntion with this one
http://forums.corvetteforum.com/c5-t...with-pics.html

Thanks,Matt

scubaman15

Thanks Matt.... great bunch of guys/gals hear I look fwd to getting to know you all !!!!!

bill mcdonald

can the elecric doors in anyway be linked to the air comming out every vent?

My vents dont work, yet I have tested and rebuilt the line and I have vacuum under the dash. Tank holds vacuum too.

Last night I found when I set the temp to 90, the air was hot, but I could not get back to cool air by setting it to 60*. I had to reset the codes (had none) while driving to get it to blow cool air.

I gather my actuator is broken too.

can the controller just crap out and not tell the solenoids to change vents?
this is the digital dual zone.

drawbondw

Bill

I would like to say thanks for such a great write up. Your pictures and instructions were right on, I was able to trace the line and found where it was leaking. I removed the battery and tray and saw that there was once an acid leak in the past. Who ever had the car before me did a good job cleaning it up though. But I couldn't find the vacuum tube, too well hidden.

After jacking the car up, removing the wheel and fender-well panel I was able locate the resevour and the two vacumm lines. I traced one up to just under the battery tray and felt it bend when it shouldn't. Found that there were two places that had holes.

I cut just past the closest one to the wiring harness and put in a new line and coupler (new vacuum line and coupler from autozone-$15 for the repair) and slide about a foot of surgical tubing over the vacumm line for added protection.

My A/C never worked so good and I have you to thank. And this site ROCKs, every problem and project I've had/solved/completed were done with the help and guidance from members of this site.

Thanks again,

Bill D.

white_lightening

In the pic you have of the vacuum reservoir, the vacuum line coming out of the top you have labeled "Inside Car". Does anyone know where that line ends up inside the car? Mine is busted very far into the wireing harness and I am affraid I may not be able to reach it in order to repair. I may end up having to run a new line, that is if I know where it ends up and I don't have to completely take the car apart to get to it.

Bill Curlee

Here is a picture of the HVAC unit that has been removed/ The loose line is the line the main vacuum line connects to:

white_lightening

How would one go about getting to that purple line? Remove dashboard?