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1996 Buick Park Avenue AC Air Flow

When running the AC, there is no air coming out of the vents. It all comes out of the defrost vents at the windshield. I have been told it could be a vacuum leak but am not sure where to find it. Any suggestions are appreciated.

There is an air valve that directs where the air should be going. If that is stuck you could have a situation you describe.

I would take the car to an independent shop specializing in A/C and they will be able to address the problem. This is not an uncommon situation.

Begin by checking the vacuum line from the intake manifold to the vacuum tank and the line from the vacuum tank to the firewall. These lines get hard and break with time.

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On my Riviera I ran a test vacuum line from the engine to the hvac controls. When the vac motor then worked I traced it back and found the line on the engine had dropped down on a heated surface and a hole burned in it. Easy fix but it could be the motor itself so if you put vac at the motor and it doesn’t work, start disassembly for a stuck or bad motor.

Thanks for the reply. But exactly where from the engine did you start the vacuum line and where are the HVAC controls?

You pick any vacuum source under the hood or the hose going to the hvac controls, it doesn’t really matter. The heater controls are under the dash. Uou’ll have to at least take down some trim panels to see the parts, then look for a/multiple vacuum hoses. A factory manual helps.

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