AC blowing out defogger/defroster vents - Page 3
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 3 of 3 FirstFirst 1 2 3
Results 31 to 39 of 39
Cadillac DeVille 1985 to 2005 including:
1985-1992 Fleetwood, 1993 Sixty Special, All FWD Forum Discussion, AC blowing out defogger/defroster vents in Past Cadillac Vehicle Discussion; Ok, I clamped off the vacuum line to the parking brake release but the A/C still shifts to the defroster ...
  1. #31
    wkearns is offline Cadillac Owners Member
    Automobile(s): 2004 Deville
    Join Date
    Dec 2010
    Posts
    35

    Re: AC blowing out defogger/defroster vents

    Ok, I clamped off the vacuum line to the parking brake release but the A/C still shifts to the defroster but only after the car has had a chance to heat up. It doesn't switch while driving (which it did before) but now the A/C switches to the defroster after the engine has been turned off and restarted (engine warm). It's acting as though the valve module which ties into the programmer goes offline after the engine is turned off and won't come back online. I'm wondering if there is a bad connection from the programmer module to the valves and when the car warms up the contacts open and the valves cease to work. Tomorrow I'll put a vacuum gauge on the valve module and see if it is receiving sufficient vacuum at all times.

  2. #32
    wkearns is offline Cadillac Owners Member
    Automobile(s): 2004 Deville
    Join Date
    Dec 2010
    Posts
    35

    Re: AC blowing out defogger/defroster vents

    Ok, I found what was causing the problem. It was NOT a vacuum leak but was instead broken solder joints on every single one of the electronic valves used by the programmer to operate the vacuum motors under the dash. I removed and opened the box up and resoldered all of the connections to the valves and replaced the crumbling foam filter with new material. Apparently the hot Florida sun caused the solder to fatigue and break for every one of the valves.

  3. #33
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    72,740

    Re: AC blowing out defogger/defroster vents

    WOW!

  4. #34
    wkearns is offline Cadillac Owners Member
    Automobile(s): 2004 Deville
    Join Date
    Dec 2010
    Posts
    35

    Re: AC blowing out defogger/defroster vents

    It was actually VERY easy to fix the part. It only has the solenoid valves, and 4 or 5 diodes and resistors and no integrated circuits. It's purely an actuator and anyone with a soldering iron from Radio Shack can fix it. No need to go to the "man mall" for parts. All of the logic and IC's are in the programmer.

  5. #35
    wkearns is offline Cadillac Owners Member
    Automobile(s): 2004 Deville
    Join Date
    Dec 2010
    Posts
    35

    Re: AC blowing out defogger/defroster vents

    Just a follow-up, the resoldering of the valves fixed the problem 100%. No more problems with the AC at all. Make sure and let the other poor guy who's struggling with this know. It's an easy fix. Bill

    ----------

    Check the valve assembly that is connected to the programmer. Remove it from the car and snap open the plastic case then slide out the circuit board. Resolder all the connections since the valves can break free from the circuit board (that happened to my '97 deville, all the valves broke free). The problem was intermittent b/c when the cabin would heat up the circuit would open and the valves would stop working. Hitting a bump would close the circuit sometimes for a short while. Resoldering solved the problem 100%.

    ----------

    Quote Originally Posted by weister42 View Post
    I have a 98 Deville and I was and am still dealing with AC blowing out of the defrost vents sometimes. My situation is different... it isn't a leak, more like a blockage or something and it is somewhere right on the vacuum distributor. It'll work just fine but all the sudden it'll blow out of the defrost vents but it goes back to normal as soon as I press or wiggle the clear part of the vacuum hose. Here is a picture of what I'm talking about...


    The AC programmer





    The vacuum distributor, not sure if that's the official name





    Here is the vacuum hose connected to the engine (the one with a T-splitter), I had to replace mine cause it was all worn out





    I think 99% of our AC vent problem lies between these three areas.

    Check the valve assembly that is connected to the programmer. Remove it from the car and snap open the plastic case then slide out the circuit board. Resolder all the connections since the valves can break free from the circuit board (that happened to my '97 deville, all the valves broke free). The problem was intermittent b/c when the cabin would heat up the circuit would open and the valves would stop working. Hitting a bump would close the circuit sometimes for a short while. Resoldering solved the problem 100%.

  6. #36
    ambisinister is offline Cadillac Owners Member
    Automobile(s): 1995 Deville Concours
    Join Date
    Aug 2012
    Age
    45
    Posts
    1

    Re: AC blowing out defogger/defroster vents

    This is the same problem I'm having on my '95 Concours. The shop I've been taking it to(which I trust), told me that the elctronic vacuum controller is worn out. The metal shaft inside that redirects airflow by the vacuum lines gets hung up because the plastic it goes through is worn. That's their explanation of how a bump in the road changes it. It allows the hung shaft to travel the way the vacuum pulls it. The shops has been trying to locate a new part without going to Cadillac, as he told me the new Cadillac part is close to 600 dollars. I'm headed to a salvage yard tomorrow to try my luck

  7. #37
    wkearns is offline Cadillac Owners Member
    Automobile(s): 2004 Deville
    Join Date
    Dec 2010
    Posts
    35

    Re: AC blowing out defogger/defroster vents

    Quote Originally Posted by EdwardP View Post
    This is my first post here.

    My mechanic installed a used AC compressor in my 95 DeVille (4.9L V8) yesterday, a new compressor was too cost-prohibitive. Once it was installed and charged, the cold air was blowing out the defogger/defroster vents atop the dash and not the front vents.

    A quick Google search on this problem showed that in 90% of the search results, the problem was a vacuum leak.

    Could someone offer guidance as to where to begin looking for this? I am bringing the car back Friday morning for this, but last night, I discovered something that looked like a vacuum hose had come apart from somewhere way down in the rear of the engine but could not see exactly where.

    Due to the location of the compressor, they had to lift the engine up in order to remove/replace and perhaps this hose became disconnected during that time, as the air (cool or warm) had blown out correctly prior to this.

    Thanks for any advice. I appreciate it.
    Apparently the parking brake has a vacuum driven actuator on it that sometimes goes bad and causes a vacuum leak that will result in this condition. If you pull off the hose to the actuator and plug it and the problem goes away, you have found your culprit. Mine did what yours did but it was the electronic valve assembly that was at fault (it plugs into the programmer and distributes the vacuum to the various actuators). I had to remove the box (measures about 1" square by about 4" long) and opened it up (it has snap tabs so it's easy to open). I found that every one of the electronic valves had broken the solder joint with the printed circuit board. By simply resoldering the joints with my radio shack soldering iron it works good as new. The problem ceased instantly and it's fine now & no recurrences.

  8. #38
    Catdiville_98 Guest

    Re: AC blowing out defogger/defroster vents

    Wow! You saved me time and money:-) Thanks wkearns!

  9. #39
    wkearns is offline Cadillac Owners Member
    Automobile(s): 2004 Deville
    Join Date
    Dec 2010
    Posts
    35

    Re: AC blowing out defogger/defroster vents

    You ware very welcome. Apparently it's due to cracks that form in the solder due to overheating.

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting