Hey guys, I have a question pertaining to 1992-1999 Bonnevilles in particular. I've never had much air from my vents, be it heat or a/c. Both work mind you but it feels like there'* very little air flow. I've replaced the blower motor fan unit or whatever it'* called because that seized up. I thought that would fix the issue. As far as I can tell my controls work (fan speed increases and decreases accordingly, temperature, etc.) I'm fairly certain there aren't any duct leaks but I'm not 100 percent sure. If anyone has any suggestions as to a fix or if I can put in a stronger blower motor maybe that would be greatly appreciated. It works but it'* not doing itself justice. Thanks in advance. My car is 97 SSEi, not that it matters in this scenario. Again thanks in advance

I dont believe Your 97 Bonneville has a cabin air filter, but it does have an EVAP core.
I wonder if cleaning that would make a difference.
https://www.gmforum.com/normal-maint...-clean-278997/
I am not familiar with the speed of fan set up...does it blow on HIGH and sounds noisy?

Is the air coming from the defrost vents as it should be from the front vents?
I am not really familiar with AC units, but I know some of them are switched via a vacuum modulator, if this is the case you may have a vacuum leak somewhere, or a line has broken off of the vacuum modulator.
There is also a blend door actuator, that could be broken.
I am sure somebody will able to provide more help on this matter soon.

It does feel like it'* coming out of the defrost vents a little bit. It'* very faint. But I have replaced the actuator door. My brother in law broke it when we replaced my heater core. I'll check the evap core. The fan sounds like it'* on high when turned up but it'* not making anymore noise than usual. Thanks for the input.

When you switch the air from front vents to the floor, does the air actually start blowing out of the floor like is is supposed to?
Or does it continue to barley come out the front vent and defroster?

I ask because it is possible it is not coming out right due to a broken nipple on the HVAC programmer, or maybe one of your vacuum lines going to it are broken, or dry rotted, if so the vacuum loss could keep the air from switching like it should, and may be the cause of the air not coming out as it should.
I found a link that I was looking for that may be of some help to you.

How To Correct Mis-directed Cool Airflow in 1996 GM C & H Cars

Now I could be wrong, and your air may be electronically switched, but I am fairly sure it is vacuum switched.

It does eventually switch to the floors and vice versa. But it always seems like there is a very small amount of air flow through the defrost vents. It does have the electronic control module thing. It'* not ***** but I'm unsure if that matters as to vacuum or electronic switching. When I get home I'll attempt to look at those things. Thanks again

Hmm, if it eventually switches then it may not be that problem, but it could be possible it is loosing a little vacuum, and maybe that is keeping it from switching over all of the way, if that little bit of air was not blowing through the defrost vent then the air flowing out of the whatever you have it selected to blow though would be stronger.

The electronic control switches are not the same thing I am referring to, you can still have the air vacuum switched, I pretty much have the same controls as you, and mine is vacuum switched.

I figured the electronic switch didn't matter. I'll check some of that out when I get home.

So I took out the glove box and all I see behind it are the ducts and a metal bar lol. Maybe I'm doing it wrong? I can rebuild my motor but I'll be damned if I can remove the glove box correctly. It'* not blowing out of the right vents anymore. The control unit does adjust the temperature and fan speed correctly though. I don't have access to my books for the car right now so maybe someone can direct me in the removal of the glove box and what not so I can check that vacuum issue. Thanks again

I am not familiar with the Bonneville glove boxes, there should be some way to remove the insert part of the glove box.
I'll try to find a video or something if possible, I did find info on a fix somebody posted on another site, it is one we are not too fond of around here, so I'll just post the text for it.

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Tools you'll need: Razor Knife, a length of 7/64" or 1/8" vacuum hose. (I used 7/64, and I liked the snug fit, 1/8 would slide on easier), a 7mm deep-well socket and/or driver, flat edge screwdriver. May need Philips screwdriver, needle nose pliers

1. Remove passenger side kick panel'* 7mm screws and wingnuts.

2. Open glove compartment, disabling rubber stops (on Bonneville, you'll need to remove the door, and the inside compartment which can easily be removed with a Philips screwdriver.

3. Look for the programmer box which will have multi-colored vacuum lines going to it, with a large orange wiring connector nearby. This is the item you're working with.

4. Begin by unplugging the pink vacuum supply line that is connected with a large orange connector to a black vacuum hose which is the vacuum source from the engine compartment. With this unplugged, start the engine and verify you have a strong vacuum at this hose/connector. If you in fact do not have good vacuum supply at this point, you'll need to first start back tracking the line into the engine bay and see where the weak link is. Check your vacuum canister first, make sure the connector isn't leaking (this is located behind the front bumper, at the extreme right front corner, directly under the battery, accessible from underneath the vehicle).

5. If you had to repair the source of vacuum, and have now corrected the source of vacuum inside the dash, re-test to make sure your problem is not already fixed. If you had good vacuum to start with, continue to step 6.

6. Locate the large rectangle connector going to the programmer box, pinch it'* protruding tabs, and pull straight out. It may be stubborn, but make sure to be careful since we're dealing with a brittle plastic case that it'* attached to. Now, feel up to the top of the programmer box, and disconnect the small motor control plug by depressing it'* one protruding tab. Once you've got those both out, look toward the bottom of the programmer box and locate a white arm that is connected to a metal rod. You'll need to disconnect the arm from the rod, which should pop off the side of it, or you'll need to remove the plastic clip from the arm by pinching the tabs together with a set of needle nose pliers. Drop the arm down and it will slide out of its place at the programmer. Next you'll need to remove the vacuum line connector from the box. One 7mm nut will need to be removed with a deep well socket, and the connector will pull straight out. Now remove the visible mounting screws, and the box should pull straight forward and tilt out through the glove box opening (mind the different wiring harnesses in the area, making sure not to pull on anything too hard.) The Pontiac dash will only allow you to bring it out through the bottom if I remember correctly, which should still be very possible once you're used to working like you have been for the past few minutes.

7. Now that you've got the programmer out, go to a good work area with your razor knife, vacuum line and flat edge screwdriver. Pry open the box cover from the edge with the orange connector and vacuum lines. Be extremely careful with the tabs. Be mindful of the additional two tabs that will need disabling at the vacuum connector and the opposite side near the smaller electrical connector. A small flat edge may come in handy here.

8. Viewing inside the box, you'll see a set of vacuum lines going to their respective control servos. Remove the black male connector at the box edge from its clip, and cut the vacuum lines as close as possible to the black connector. Now, slide the long clear vacuum manifold from the control servos (this will make it easier to work with, being the length of the remaining lines is short.) and take it out of the box. Cut 5 sections of 3-4" vacuum line and begin fitting them to each color of line where you just cut the black connector off. If you're using 7/64" hose, it'* going to be a snug fit.

9. Take your programmer box, lid, razor knife and newly fitted vacuum line set and go back to the car. Now, go to the clear female vacuum connector that once connected to the black box, and cut the lines as close to the connector as possible. In some cases, the colors internal to the programmer, and external that run to the air distributor will be different. Take your now individual connectors and put them back together. This will easily tell you what color lines will go together. Connect all the lines to the new vacuum hose, matching the colors as the connector would. Make sure all the lines go into the hose at LEAST 3/4" to ensure good seal, and that they won't pull out if yanked on for any reason.

10. Now slip the long clear vacuum manifold back onto the male servo connectors, making sure to seat them fully and evenly. Without pulling on any part of the vacuum lines, route them back to the same hole where the connector once sat, and re-install the lid onto the programmer box. Begin fitting the box back into its installation location in the dash. Make sure to seat the locating tabs on the back edge of the box first, then install the screws. Installation is reverse of removal. 2 electrical plugs, one white arm going to the metal rod and all vacuum lines should be double checked for security in the vacuum hose connection. Don't forget the pink hose that goes up to the vacuum supply!

11. Once all connections are verified, before installing glove box and kick panel, start the car, and check the function of the vents. At this point, if all went well, assuming there are no additional issues with the system, you should have full vent mode function! Keep in mind that the programmer was reset by being unplugged, and may take up to 30 seconds to fully answer to a mode command.

12. If all is successful, install your glove box back, as well as the kick panel, and you're good to go!