AC-Defroster Questions - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 08-03-2006, 01:27 PM   #1
Senior Member
Posts like a Turbo
Thread Starter
 
Join Date: Feb 2006
Posts: 220
Thanks: 0
Thanked 0 Times in 0 Posts
NCCamper is on a distinguished road
Default AC-Defroster Questions

Hi Gang,

My AC flow is being directed probably 75% through the defroster vents, and the rest through the dash vents. This is no matter which setting I have the control set to. I understand there is a door inside the ducts that directs the air flow to the proper place. Is this door prone to getting stuck? Is it vacuum or electrically or mechanically controlled? Or, is it possible the control itself is the problem? BTW, if it makes any difference, my stereo was stolen the other day, but it looked like a "clean" heist...no other damage, except for the cracked trim. I put my stock AM/FM back in - it plugged right in. Could the thief who ripped me off disconnected something?

Also, my Bonne just has the basic AC controls.

I appreciate the help.

Thanks,
NCC
NCCamper is offline   Reply With Quote
Old 08-03-2006, 05:30 PM   #2
Senior Member
Posts like a Northstar
 
Join Date: Sep 2005
Location: Dayton, OH
Posts: 600
Thanks: 0
Thanked 0 Times in 0 Posts
imidazol is on a distinguished road
Default Re: AC-Defroster Questions

Quote:
Originally Posted by NCCamper
my stereo was stolen the other day, but it looked like a "clean" heist...no other damage, except for the cracked trim. I put my stock AM/FM back in - it plugged right in. Could the thief who ripped me off disconnected something?

Also, my Bonne just has the basic AC controls.
Sounds like one of the little 1/8 inch diameter tubes to the vacuum motors got disconnected. I spent lots of closeup time with my 98 vacuum setup but it'* the computer controlled type.

I suspect the tube for the valve that closes off the defroster duct and makes the air come out the dash instead of defrost is off or the vacuum motor has been damaged or loosened in some way.

Do you hear the motors move when you select heat and bilevel and each of the other settings? Run the car for a second to build vacuum and then quickly punch through those buttons. If yyou hear the movement, that means you're getting vacuum.
imidazol is offline   Reply With Quote
Old 08-03-2006, 05:36 PM   #3
Senior Member
Posts like a Turbo
Thread Starter
 
Join Date: Feb 2006
Posts: 220
Thanks: 0
Thanked 0 Times in 0 Posts
NCCamper is on a distinguished road
Default

Thanks for the reply.

I will check closer, but I was listening for the opening/cloing sound of that door, and I havent heard a thing. If I wanted to track down a loose or damaged vacuum line, where should I start? I know there are several on the other side of the firewall, but I suspect that "door" is behind the radio/climate controls somewhere. This vacuum motor, where is it located?

Thanks for the response!
NCC
NCCamper is offline   Reply With Quote
Old 08-03-2006, 07:00 PM   #4
Senior Member
True Car Nut
 
Join Date: Jul 2004
Location: Grand Rapids, Mi
Posts: 5,656
Thanks: 0
Thanked 0 Times in 0 Posts
Archon is on a distinguished road
Default

This is a thread with a similar problem. It should answer most, if not all of your questions.

http://www.bonnevilleclub.com/forum/...ic.php?t=59735
Archon is offline   Reply With Quote
Old 08-03-2006, 08:08 PM   #5
Senior Member
Posts like a Turbo
Thread Starter
 
Join Date: Feb 2006
Posts: 220
Thanks: 0
Thanked 0 Times in 0 Posts
NCCamper is on a distinguished road
Default

Thanks for the replies. They are helping.

And now for more info. I checked for the sound of the door closing/opening...nothing. As noted above, my Pioneer HU was stolen out of my car. Temporarily, I replaced it with my OEM AM/FM/ Cass stereo. Basically, the unit slides in on a center track, like a drawer in a dresser. When I removed it this afternoon to look around, the AC was redirected out the dash vents, and stopped coming out the defroster. Not so fast! Now, I don't get anything out of the defroster, even when it'* set to defrost. So, I helped one problem while creating another. What'* the common thread between these 2 issues? I cant see anything behind the stereo that would cause the original problem to happen (like something crimped or disconnected). Any more thoughts/suggestions?

I will look into the vacuum hose as suggested in the linked post.

Thanks again!
NCC
NCCamper is offline   Reply With Quote
Old 08-03-2006, 10:58 PM   #6
Senior Member
Posts like a Northstar
 
Join Date: Sep 2005
Location: Dayton, OH
Posts: 600
Thanks: 0
Thanked 0 Times in 0 Posts
imidazol is on a distinguished road
Default

Quote:
Originally Posted by NCCamper
Thanks for the replies. They are helping.
When I removed it this afternoon to look around, the AC was redirected out the dash vents, and stopped coming out the defroster. Not so fast! Now, I don't get anything out of the defroster, even when it'* set to defrost. So, I helped one problem while creating another. What'* the common thread between these 2 issues? I cant see anything behind the stereo that would cause the original problem to happen (like something
NCC
Does the control change things like heat and bilevel settings? Do you hear motors moving there like I described earlier?

Did you mean that when you pulled the stereo out the dash vents started working and the defrost won't or is it just that now it'* working that way? If so the second could mean a valve or motor that'* sticking. The hose to the vacuum motor will be blue. There are three vacuum motors. The motor to the left facing down is the recirculate, the one to front is heater, ac, bilevel, and the one upmost of the three with the connection for vacuum on top is the defrost ac valve. You might try pushing in on the diaphragm. the diaphragm has a spring that makes it go to defrost setting unless there'* vacuum pulling it in and then the valve inside the heater box is moved to dash vents and the defrost blocked.

A quick check once you get to the blue valve is run car motor briefly and put damp fingertip over end of vacuum hose; the vacuum will stick to your finger when you select AC setting; no vacuum when you select defrost. If no vacuum in either setting, then you have vacuum loss somewhere else along the line.


To see these, you take off the hush panel under the passenger dash. I don't believe I had to take off the hush panel on the driver'* side.

I'm working from a Buick manual for 93; but the Bonneville should be the same heater box.
imidazol is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Questions,Questions,Questions.......... dbeast420 Lounge 2 05-06-2006 03:49 AM
Rear defroster ?'s 1993 SLE Everything Electrical & Electronic 16 02-24-2004 11:23 PM
Rear window defroster switch?? HDvorider2001 Everything Electrical & Electronic 4 01-20-2004 02:10 AM
Defroster Problem?? Boberle1150 1992-1999 1 09-28-2003 10:08 PM
Questions questions questions big_boss2010 1992-1999 2 09-06-2003 01:41 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 04:59 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.