AC/mid vent doesn't work

[DakotaKLR600]

I have a 1996 Buick Park Avenue Base the AC and mid fan setting do not work. Sounds crazy but was in a car wash one day and the mid vent just started working out of no where... (Quit after exit) I feel like this is caused by a vacuum line, or blockage. I saw a similar post on forum some time ago, but it included some pictures that had expired. Any help would be appreciated!

 

[HotZ28]

Check the vacuum lines from the intake manifold under the hood to the inside programmer. 1996 was mostly vacuum actuators.

 

[2007LucerneCXL]

These may help

 

[DakotaKLR600]

So I have not figured out the mid-vent issue, but I did get the compressor clutch to engage. Sound like complete BS I know, but hit the AC clutch with PB Blaster with the engine running and AC turned on, R134a refrigerant refill attached and cycles AC controls a few times. Was holding the AC recharging unit and POP the clutch engaged?! Total fluke but I'll take it, system is about 35 PSI, mid vents still were not working but at least it cools the car!

 

[DakotaKLR600]

WIN!!!! If you lay under the passenger side front bumper and look up the vacuum canister pictured will be right in front of your face. (under battery box) The elbow with an arrow was mouse eaten and when I touched it cracked. I pulled it off and use a small piece of new lawn mower fuel line to splice the vacuum line to that canister. IT WORKED!!!! Charged AC system, and now my wife will have AC for the summer I am so happy!!! Hope this helps someone in the future!

 

[DakotaKLR600]

 

[2007LucerneCXL]

Glad you found it, unfortunately no way to know which vacuum line is the problem over a forum and all are suspects.

 

[BuickGirlFromMars]

View attachment 37731

Huh I didnt know that the line had a vacuum tank under the battery area. glad you found it, but i thought it was a tank on the cowl lol. anyway, it looks like that line going from that check valve is the one your tank is hooked too. if your line is truly in okay condition, and your splice is short, then id say its fine. but if you have it anymore than half an ich, I would change it out with a vacuum tubing hose or new elbow(should be able to find in store) at earliest convenience

 

[BuickGirlFromMars]

if you were ot have this issue again id say check this. if you were to turn your ac off, drive and find a hill, lets say
go down it, while going down, be off the throttle, turn on the ac and to a vent, youd prob get something ASSUMING the vacuum leak wasnt present at the hose. If you did, that would tell me the tank is to keep and allow things to work without interuption. then if you were to have a leak, the check valve should do the same thing. but you would loose the setting if your vacuum bled off or you had a supercharger and you were into boost

but if the check valve is good with the tank, if you WOT somewhere you may eventually lose your setting. Just rambles

 

[BuickGirlFromMars]