Can anyone help me out? I have a 1996 Bonneville with climate control and I charged the A/C today but can only get the air to come out of the defroster and floor vents, not the center face vents. I checked the manifold vacuum connection, the vacuum canister under the battery tray, vacuum lines on the rear of climate control unit, and manually operated the door on the unit inside the car by the floor ducts and cannot get the door to operate like it should using the control panel. Anyone have any ideas? I suspected a vacuum issue or is there a fuse or electrical issue I may be over looking? Any help surely will be appreciated! Thanks~

If you run the motor to build vacuum, turn it off for quiet, and leave the key ON, do you hear hear some doors move as you push different buttons on the dash control?

If you get some doors moving but not the dash doors, try moving the diaphragm for the dash--it has a blue vacuum line to it. You can also switch one of the other door'* lines to it to see if it operates when those other doors are given vacuum--or run a line directly from the intake manifold connector.

Then your check is to disconnect the violet line from the programmer box that goes to the C-pillar and through the firewall to the engine compartment and check for vacuum there if you're not sure you're getting vacuum.

Most likely it'* the collapsing of the nipples in the vacuum connector. Bypass the vacuum connector with 7/16 inch vacuum line. See this old article.

http://www.imcool.com/articles/airco...acuum_line.php

Your HVAC mix actuator doors are vaccum controlled. Read this write on troubleshooting that system.

https://www.gmforum.com/mechanical-134/default-redirect-cooled-air-late-model-gm-cars-96-2000-a-279092/