Hey guys. Have a 91 Z with some HVAC problems. Minor, but they still bug me. For one, I cant go directly from "Off" to "Vent". I have to go to "Defrost" first, wait for it to stop hissssssssing, then go to vent and I hear the doors rattling around and the vent setting works. Second, "Floor" setting for heater doesnt seem to work. Almost does the same thing as the vent problem, but the selector doesnt want to "click" into place, if that makes sense. I move it to "Floor" and it just sits there and I hear vacuum releasing ... hissssssss. Any ideas for me?

Brian

 

I feel slightly dirty doing this, but I'm having HVAC issues too, somewhat different, control realated though.. If someone out there just happens to know a lot about the HVAC thingy, here's my thread, ni the electronics forum.. No replies.. Thinking back, maybe not so electronic..

https://www.thirdgen.org/techbb2/sho...hreadid=349000

Thanks.
And again, apoligize for the thread jack..

 

Hey man, if we can both get some help, works for me

 

Seems to me like no one knows anything about them.. . But then again, neither do we..

 

Ive once had a similar problem.I know there is a rotary dial on the HVAC unit.You have to remove the HAVC first.The rotary dial is on the right side of the hvac unit.There are about 6-8 VACUME tubes on it.There is 1 main vucume tube from the eng compartment(purple i believe).The rest are for your various heat/air settings.The dial rotates in relation to the heat/air lever.Anyway the hiss could be coming form there.Sometimes the tubes slip out slightly & cause the hissing &/or your vents not to work properly.You should also check to see if a tube(s) are cut or have a hole.Basically check all the tubes/diaphrams,etc for leakage/damage.