middle a/c vent - Page 2 - 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.

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Old 06-23-2003, 02:29 PM   #11
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i'll check that out and let ya know
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Old 06-24-2003, 09:35 AM   #12
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ok so i took a look with my car and a/c on, no hissing noises and everything is sealed. i turned it off, took out the vaccum tank and when i unhooked the one vac line, it sucked in air, (i'm thinking cause i doubt it would let pressure out), and made a hissing noise then.(this has to mean everyhting is tight) i hooked it all back up and my a/c still blows cold but only through the top and bottom. any more ideas?
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Old 06-24-2003, 02:31 PM   #13
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Have you got electronic climate control?
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Old 06-24-2003, 03:18 PM   #14
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yep
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Old 06-24-2003, 03:49 PM   #15
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Is your problem that the arrows will not point to the middle vents? Can you get them to point to the middle vent?
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Old 06-24-2003, 04:09 PM   #16
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i can get the arrows to point to which ever but it only blows out the top and the bottom
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Old 06-24-2003, 05:41 PM   #17
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Quote:
Originally Posted by 95naSTA
i can get the arrows to point to which ever but it only blows out the top and the bottom
I know it seems like we keep hammering on the same point here but just so we're clear on this: Can you get the display to show you arrows coming straight out of the center vents of the diagram? There are three possible arrow positions, top, bottom and center. (Duh. ) We want to be sure the system is really aiming for the _center_ vents, what you usually get with an A/C setting. Anytime it tries to invoke extra heating, or if the user presses the Defrost button, it'll go to floor registers or windshield ducts respectively.

If you've got the middle arrow(*) showing, you should indeed have air coming out through the dash. You should also hear some sort of wheezing noises in the dash whenever it tries to change settings. Since you have already verified that you've got vacuum going to the booster/reservoir under the hood, you need to figure out where the vacuum connection is going between the reservoir and the dashboard; i.e. follow the vacuum line under the hood to wherever it goes through the firewall, pick it up again on the other side, etc. Somewhere along the line you have a disconnect, or perhaps a vacuum component that'* broken.
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Old 06-24-2003, 06:18 PM   #18
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lol. On my display i can change it to blow out the center vent with the arrow pointing from the center. But there is no noise of changing directior or any air coming out of the center vent. Could it be possible that the hoses going into the vaccum tank are backwards? i'm guessing if that thing is completely hollow then no.
so is all that'* left is to pull out my dash and follow the vac line????
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Old 06-24-2003, 06:35 PM   #19
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Quote:
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Could it be possible that the hoses going into the vaccum tank are backwards? i'm guessing if that thing is completely hollow then no.
Um... well, it'* not completely hollow; in fact I think it has a one-way valve in it to prevent temporary vacuum loss from hard acceleration, and I don't _think_ the two ports are exactly the same size anyway, so it should be kind of hard to plug them in backwards. Mainly what you're interested in there is to identify which of the two hoses is the _output_ one that goes into your dash, and just verify that the port on the booster/reservoir that it'* plugged into is actually drawing vacuum when the engine is idling.

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so is all that'* left is to pull out my dash and follow the vac line????
Wellll... I dunno if I would pull the dash right away, but it sounds like you have narrowed down the problem to someplace between the reservoir/booster and the dash controls. If you've had any underhood or dashboard work done recently, I'd start by poking around there and see if something got disconnected. Look at it this way: the problem is most likely going to be found someplace that'* _already_ accessible, if it was caused by somebody bonking a vacuum part and knocking off the connection.
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Old 06-25-2003, 12:43 AM   #20
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Here is something I found on the internet a while back.... This may be your problem. I can't seem to be able to post the pictures that go with this article. Please E-mail me for the complete article with pictures.

Jaime

1996 General Motors "C" cars (Oldsmobile 98 & Buick Park Avenue) and 1996 through 2000 General Motors "H" cars (Pontiac Bonneville, Oldsmobile 88, and Buick Le Sabre)óall with automatic airómay be blowing air conditioned air out of the defroster and heater outlets instead of the a/c vents. A likely cause is the weakening and subsequent crimping of one or more of the vacuum lines, or softened connector nipples within the A/C programmer. If you verify this symptom and want to correct it, hereí* how:


Figure 1. This is the male connection in the programmer showing flexible rather than firm nipples, and a broken nipple. This harness will not work! But with a little modification, you can replace it with one going as far back as 1985.

1. Release and fully open the glove box. This will expose the air conditioning programmer and multi color vacuum hose harness assembly. The vacuum source hose from the engine is black and connects to a violet flexible plastic tube going to the programmer vacuum connector plug.

2. With the engine running, locate the connector on the violet tube where it connects to the black vacuum hose. This connection is about six inches from the programmer. Disconnect the two hoses at this point to verify that there is indeed engine vacuum.

3. If there is not, you have a vacuum source problem. Identify the problem, repair it, and test again for vacuum and for proper air flow to the vents.
If the problem is solved, skip the rest of the steps and fill out the customerí* invoice. If there is vacuum present, you will have to keep searching. In all likelihood the problem is in the male vacuum connector attached to the programmer.

4. Remove the 8mm nut holding the female plug and gently unplug the female manifold vacuum hose connector.

5. Check the male connectors. If they are soft and flexible, this is the problem. Often in addition to being soft one or more of these nipples will break off and remain in the female connector.


Above: Figure 2. This shows the clear plastic female connector in place on the installed programmer with the suggested flat washer (circled in red) added for strength.


Below: Figure 3. This shows the interior of the opened programmer exposing the offending hose harness assembly. This assembly will need to be replaced or bypassed with 1/8 inch vacuum hose.

Unfortunately this harness assembly is not available as a service part. However, a similar programmer is used on "C" and "H" cars back to 1985.

Swap out the Harness from an older programmer
6. To proceed with the following repair, first remove the programmer from the vehicle. Trying to fix it while still installed will invariably lead to cracking the case.

Above: Figure 4. This clear, plastic female connector may have one or more broken nipples. If a replacement programmer or harness is not used, and a repair is needed, cut the connector off and bypass with 1/8" vacuum hose.
7. If from a used programmer, you can salvage a male connector with firm vacuum studs, open the offending programmer and replace the harness assembly as shown in Figure 5. Put the cover back on the programmer and reinstall in the vehicle.

8. Before connecting the existing clear plastic female connector, you will need to carefully extract any broken nipples that remain. Now gently push the female connector onto the male connector you replaced in the programmer. Be sure to reinstall the nut using a flat washer. Without the washer the connection may not properly seal. (See figure 2)

9. Start the engine and set the controls for cool air. Remember, once the programmer is disconnected electrically it loses its memory. After re-connecting it and requesting air conditioning, it will take a couple of minutes for the system to function as directed. Retest and check again for proper airflow. If it works, youíre done and you can forget the repair below.

Above: Figure 5. The culprit: no one is sure why the hoses of this harness assembly become so soft that they crimp and cut off vacuum. But they do, and then chilled air is sent to the wrong vents. This assembly is the same one shown in Figure 3, but removed from the programmer.
If you can find an old programmer, swap out the harness. Look for GM #16258434 or AC Delco #15-72278 (fits a Buick). However, there are several programmer part numbers using the same harness. Donít settle just for this p/n.
Plan B: Repair the existing programmer
If you cannot locate a replacement harness, plan on repairing the existing unit.

1B. Remove the programmer from the vehicle.

2B. Open the programmer and carefully cut the colored plastic tubes at their point of entry into the black connector.

3B. Cut off the clear, female connector. Reconnect each individual hose (color to color) using 1/8-inch vacuum hose.

4B. Complete Step 9 above.

I suggest that you also record on the repair order the inches of vacuum at idle. No amount of system repair can compensate for an engine that needs mechanical attention and is not producing adequate manifold vacuum. Please measure with a proper vacuum gauge.

Certainly, another option is just to replace the programmer. With a suggested retail price in excess of four hundred dollars, the option is a bit pricey, especially for an older vehicle.


This worked for me!
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