i have a 1991 olds cutlass ciera. i just replaced the whole blower motor and now air is coming out of the defrost vents only. it was set to vent when i changed it but now its blowing out of the defrost vents no matter what i set the selector to. the only thing i removed was the whole aircleaner assembly so i would have better access and all i did was move it aside under the hood.i don't see anything that appears to be dissconnected. can you help. the vent selector worked no problem before so something got damaged during the repair.

Sounds like you knocked off the vacuum line for vacuum motor actuator. with no vacuum it defaults to the defroster. Look around under the hood by the firewall where you were working & you should find it.

looked by the firewall did not see any broken lines. the only lines i see are a wire that goes from the engine to a T with 2 other wires which run along the firewall. does it matter that this is done without the engine on. just the key turned to on so everything but the engine is on thats how i tested the new blower and found out its in defrost. is it possible the vacuum motor quit.



all wires look intact.

Those aren't wires. Those are the vacuum lines that Sidom referred to. They are plastic lines and the crack and break very easily when handled. You need to inspect that line carefully and find a place where it cracked. If you can't find it visually, then you will have to use a vacuum gauge to determine where you are losing the vacuum supply.

You can rtepair them by splicing them with a small piece of the correct size rubber vacuum hose.




78 Corvette Pace Car For Sale-18k mi orig-Florida




(This post was edited by Hammer Time on Jun 20, 2009, 3:30 PM)

well guess what. turned the engine on and the vent works correctly. i just tested the blower by turning the key to on and it was blowing in defrost mode. i figured it was controlled by a cable. learned something new today. the engine has to be running for the vent control to work unless there's a problem with the vacuum motor.

Generally vehicles use a vacuum storage device - GMs a plastic ball to maintain vacuum while engine isn't providing it. There will be a "check" valve - I think shown in your pic that will only allow flow one way. Any vioation or leak the vacuum controls won't work with engine off. By the looks of things if you take the vacuum hoses apart to check they willl break so it this is just a minor inconvenience for now leave it alone. Those plastc vacuum lines are about the integrity of uncooked pasta after a few years. If you notice going up hill or engine under load it defaults to defrost it's time to chase down where it's leaking,

T
_________________________________________


Tom Greenleaf - MetroWest, Boston
http://acsource.net/acforum/index.php