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A/C blowing on floor and windshield FIXED

I'll let you know, ghfun. I'm not taking it in for a week or so. I have a few other projects I want to do beforehand, including banging a few gears...:D
 
Just ran across both the web site and this posting - which caught my eye.

My C68 Electronic Climate Control Buttons (C4 1990 Coupe) have been working intermittently for the past 12 years - and I finally decided to try and tackle the problem this fall.

Here's my read on the situation - and would appreciate any suggestions or confirmations...

From what I've read here, I'm hopeful that the vacuum connector on the programmer may be my problem - solved by improving the attachment mechanics (especially in as much as I've had problems from nearly the beginning - 1991)

**

The buttons seem to operate with a mind of their own - sometimes they work, sometimes they don't. I can turn the car off and on, same problem continues to exist. I can wait it out - sometimes 20 minutes, sometimes 2 days. But eventually they become functional again (and perhaps another becomes temporarily non-functinal).

I have no fault codes stored in the system - and have never had any...

1) Would the fact that they operationally fail inconsistently, as opposed to constantly fail indicate a particular problem area (IE: programmer, control head or vacuum)? I read postings where the same problem has been solved by replacing the control head, replacing the programmer and fixing vacuum problems.....

*****

I've been told that '89 and earlier dashboard push buttons need to have the button contacts cleaned from time to time to ensure that theyare operating properly. '90 and later should not require cleaning, the design was changed. Don't know if this is true or not. I've never tried to clean my buttons.

The same source suggested that I unplug and replug the HVAC programmer and see if that solved the problem. If it didn't - it was most likely that I needed a new programmer (don't know why I had to unplug the programmer vs. disconnecting the negative battery cable...).

*****

I did just that (disconnected the programmer), and all buttons started to work again. Several days later, the problem returned. Each day, it's a different button that refuses to work... Today the off, AC and recycle buttons are not working - everything else is. In the past, temperature and fan control buttons were also affected.

I note that disconnecting the negative battery cable and reattaching it allows the programmer to reprogram itself (in case the logic was previously lost or screwed up).

2) Would screwed up programmer logic affect the activation of the buttons - or merely the requested activity setting at the other end of the HVAC outlets?

********

Still not sure if the problem is programmer or control head related.
I've reviewd the Diagnostic Flow Chart for the C68 Electronic HVAC in the Shop Manual for the '90 C-4 (page 8A-62-5).

This appears to be the checklist I have been seeking that will help me determine if my problems are programmer or control head related (or heaven forbid - radio control head...yuck).

99% of the tests appear to be checking for wiring shorts or open grounds using a test light attached to pins on the control head wiring harness (with programmer sometimes attached and sometimes disconnected).

The final test is the one that is probably the most interesting - attach a scan tool with E & C capabilities to the ALDL connector and control HVAC functions with the scan tool.

If there is no control - replace the programmer.
If there is control - replace the control head.

Unfortunatley, I don't have a E&C scanner - so I continue to read the web sites.

Which brought me to this thread.

***********

The possibility of vacuum problems intrigues me (and might explain the works / doesn't work issues).

When I had the programmer disconnected (electrically), I left the vacumn hose cluster attached because I couldn't find a socket to inbetween the octopus hose cluster (and didn't know what I was doing). The manual shows a nut holds the air valve actuator vacuum harness onto the programmer.

1) What size nut is this?

2) Do I neeed to remove the hoses from the harness assembly connector (hopefully not - don't want to screw up the positioning)

{As you know, need to remove the connector while under the dash - limited mobility and visability}

***********

If a pinched hose - how would I tract that down w/o having to take the entire dash apart and check the hose routings?

***********

Finally - I'm not clear on the "vacuum T check valve" on the right side of the engine - What am I looking for and where would I find it. I'd like to check it out to ensure it is working properly.


Whew - what a post.

Thanks so much.....
 
Where'd the pictures go?

f18_builder said:
This is really late, but this post helped me out, and I wanted to add a few notes from my efforts.

I am going to attach some photos of the repair to help future owners.

Here is what I did:

Removed the lower panel on the driver's side 6 fasteners (see picture).

unscrewed the ODBII connector, and unplugged light.

pulled the hood release to allow the panel to slip out (see photo)

Do ever back strecthing exercise you can think of....

stick your head by the gas pedal and look up.

The connector on mine is green rubber with colored hoses coming into it (see picture)

My nut was already off the connector. I flattened it with a hammer to get it ready to go back on. I probably should have purchased a nut to put on the stud instead.

I disconnected the connector, started the engine, and felt for the suction on the black source hose.

I got a deep well socket to match the nut that was holding the ac programmer to its bracket. I tightened the nut as much as I could (by hand!!!!!!!)

I didn't have any grease, but I would have liked to put a thin coating of grease on the connector to help seal the vacuum ports and to allow it to go on easier and better. Watch what you use! Don't put something on the rubber that will desolve it over time.

I put the connector back in place and pushed until I had a good seal. The vents worked perfectly.

I think this next step will help if you choose not to use a nut to retain the connector. ... I put the retainer on the post. Next, I got a small diameter deep socket and used it as a ram-rod on the retainer to securely seat it. I think it worked well.


I really think some grease would have helped... long-term. I will try it next time it stops working!!!!!!

Hope this helps someone in the future.
I've got the same problem as everyone else now. But where did the pictures go? Do they get deleted off the server after a while?
 
swore i was goin to do mine in the winter while it was cool..
ran out of time.. and not its hot!
 
Wow, I lucked out. I pulled the engine cover and there it was: a broken plastic check valve and a vacuum hose laying on the engine. $6 for part number 14056648 and it's done. If anyone hasn't gotten around to checking under the hood, do yourself a favor. You might just have a ten minute repair.
A huge thanks to all who contributed to this thread!
Ken
 
For the longest time I thought my actuator door was broken or that I had the dreaded deteriorating vacuum hose problem, because my a/c comes out through the vents as well as into the footwells. Well, today I looked at the door schematic in the service manual and it turns out that some of the a/c is actually routed to the floor intentionally. All this time I thought it was broken but it isn't. It certainly pays to have a service manual, because I've never owned any other car where the a/c was routed to the floor. Weird.
 
Hi i,m having the same problem (ac blows bottom-top only) and i did notice a broken vacuum line next to ecm in engine bay but can't find where it goes.Anybody have schematic or pix of where the line goes?I'ts the one coming from the T, also noticed missing? line under passenger side fuel rail cover.I'ts hot down here in Miami and taking too long for bottom vents to make interior comfortable.
Thanks, David (davidlt4@bellsouth.net)
 
davidlt4 said:
Hi i,m having the same problem (ac blows bottom-top only) and i did notice a broken vacuum line next to ecm in engine bay but can't find where it goes.Anybody have schematic or pix of where the line goes?I'ts the one coming from the T, also noticed missing? line under passenger side fuel rail cover.I'ts hot down here in Miami and taking too long for bottom vents to make interior comfortable.
Thanks, David (davidlt4@bellsouth.net)
Here's a diagram out of the 1996 repair manual. Item 24 was the valve that was broken on my car.
Ken
 
Thanks for this writeup. When I looked at the T, the hoses seemed awful fresh (not hard or cracked), but there was no vacuum. There was vacuum ahead of the check valve, but not after it. I checked the valve, and it seems someone installed it backwards! Now all of my vent controls work. In addition, the cruise control which had been undependable suddenly works right!

Bill
 
ghfun said:
I am going to find a longer screw for the connector, put a spacer on it so I have room to tighten a real nut for the screw. This should hold it tight and will completely fix the problem. Thanks again to all who responded.

Mark

Funny how folks come to the same conclusion. That is exactly what I did a few years back, put a short piece of hard rubber hose over the stem so I could tighten a nut with better access back away from down inside the manifold. It has been working great now for several years. (man, I hate I said that...now it'll probably act up again)
 
HELP.....?????????????????????????????

I have tried and tried to get the retainer off the vacuum line connector with no luck....I cannot even see this retainer! I can almost get one hand in there to try to pry this retainer off (that I can't see in the first place)!!

How in the world did you guys get this retainer off?????????????????? Need hints...what works???????????????

LannyL81
 
A good chiroprator and patience.

Really small needle nose pliers. Try to carefully spread the vacum lines away from each other to get a better view of the black retainer. The vacum lines do have a little play in them but you have to be careful when flexing them back and forth. It is a pain in the back, my back is still hurting from sunday under the dash too. I'm going to attempt to take the nut off that I put on about a year ago that fixed the problem for about a week. So tommorow I'm going to add the washer that everyone says will get a better seal on the vacum. If that doesn't work I'm going to drive it in the lake, because that is what the next step is to do!! LOL :)

"Vette96ce" Jim
 
A few things to keep in mind:

Your connector on the programmer can be TOO tight OR TOO loose. Either situation will render the programmer useless. A very happy medium has to be met!

Your cruise control vacuum come from the same place that the A/C vacuum comes from. If one does not work, usually means the other one does not work either.

Your vacuum canister (black round plastic ball) can be found right behind the front bumper on the driver's side. Sits next to the electrically controlled air pump. This is on late model C4's. Vacuum runs to the canister and then comes back to the cruise control actuator and also runs thru the firewall to feed the A/C system.

Be sure to check ALL of your vacuum lines for hardness, brittleness, holes or breaks. Very easy to repair them. Just replace the hose that is bad. You do NOT need to replace the entire hose assembly.

Save The Wave! :w
 
Update

Well I got the $^@#!$$!!! retainer off!!!! What a complete PITA job.

Took out the controller and put in a longer screw and used a plastic spacer and then tighten with fingers only. Also sprayed the vacuum lines connections with some silicon to help them seal. I also found the heat shield over the footwell light was broken loose so I pop-rivet that back in place.

This is one job that I never want to do again.

LannyL81
 
LannyL81 said:
Well I got the $^@#!$$!!! retainer off!!!! What a complete PITA job.
This is one job that I never want to do again.LannyL81
If it is under the dash , I really don't want to do it!:ugh

Glenn
:w
 
Update #2

Just got back from taking the car out and all I get is air blowing out the defroster vent no matter what button I push on the electronic temp control.

Guess I will check that check valve under the fuel rail or just replace it if the local dealer has one. But where do I go if this is not the problem???

LannyL81
 
yank the seat out --then put both feet into the rear compartment and work in total comfort laying flat on ur back..saves time in long run
just pop the retaining wire at the front edge of the bottom cushion to access the elec connectors,remove bottom cushion, (4) 13mm nuts hold the seat in...the nuts are 'deformed self locking' and a bit of pain to remove the first time.
get a flourescent type trouble lite with small diameter head---easier to fit in,more lite,no chance of burning u or the car
 
I had kind of the same problem, found out I had tightened things a bit to much and clamped off some of the control and vacuum lines on the control module.

Hope this helps . . .
 
sigh -
I STILL need to do this to Susan's C4..
 
When anyone does this task...one has to remove the driver's seat so that you can have somewhere to put your body. I cannot imagine doing this with the seat in.

I checked the check valve under the fuel rail...took off the hose between the valve and the intake...nothing happened. Took the line off on the other side of the valve and had vacuum that was slowly releasing. So I am assuming that the check valve is good as it was holding vacuum.

Will have to take the seat out (again), the lower dash trim panel (again) and check for vacuum at the programmer. I am then going to try using my Mighty Vac on the different lines and check the operation of the different doors. I hope I do not have a bad vacuum motor as this probably requires removing the dash.....and that does not look to be much fun!!

Later,
LannyL81
 

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