No air coming out the defroster 1985 suburban

[JohnnysCamaro]

No air coming out the defroster 1985 suburban

Hello, changed oil yesterday at a garage, they noticed a few vacuum hose needed replaced with bulk tubing. Today I’ve got plenty of air coming out the floor vent a little bit coming out the dashboard vents but practically nothing coming out of the defroster vents. Any connection here? It’s a good garage, and well respected in good reputation but they might be just a little bit too high tech. Not much gray hair back in the bays.

Thank you all and have a safe and prosperous and healthy new year,

Jonathan Smith

[Palf70Step]

That is controlled by a vacuum hose. Could be one under the dash that is bad or one that is bad/loose in engine compartment. I do not have a diagram of what goes where, but had to redo severl GM vehicles hoses because of that issue.

[JohnnysCamaro]

Bill
Thank you greatly! I found a mechanic in Greensboro who has experience with old Chevys and he says he is the man to fix this. Says there are only 4 persons in Greensboro with this experience, and two of them are in his shop. Am I lucky or what?

Blessings,

Jonathan

[Dead Parrot]

If the problem started about the time the first garage 'fixed' the vacuum hose problem, likely they missed reconnecting the round vacuum canister on the firewall that connects to the inside the cab climate control system. IIRC, the default no vacuum positions are bottom heater output and no recirculate.

Could also be that the 34 year old system failed about the same time but was unrelated to anything the first garage did.