Buzzing noise stays on while car is on 1981 Porsche 928

[sdmike928]

There is a loud buzzing noise coming out in between the vents and the radio. It stays on all the time and it's driving me crazy. At first it would buzz when I turn the car on and go away after some seconds but recently it stays on. Not sure what it can be but any help or pointers would be greatly appreciated.

[Danglerb]

Nothing normal I can think of buzzes in that location, zero chance it will heal, but something partially broken might fully break.

Maybe related to something in the blades of the temp sensor or main AC blower?

[Landseer]

There are vac diaphragms for hvac actuators. If they tear they can buzz

[928gene928]

Mike,
I agree with Landseer, there is a very good chance that it is a vacuum leak from the HVAC controls. I had a similar noise at one time, and that is what it was.

[neil30076]

Look for the vacuum line going through the bulkhead and trace it back to the 'T' it connects into. Pull it off and plug the 'T'. If noise goes away the diagnosis is confirmed. You may be able to get to the line under the dash by removing the drivers side panel under the console and looking up in there, although it may not be visible, and you need small hands

[Mrmerlin]

read up on this it should answer most of your questions.

http://r.search.yahoo.com/_ylt=A0LEVrd5lBpVWYQADyMnnIlQ;_ylu=X3oDMTE0dXEycnR nBHNlYwNzcgRwb3MDMgRjb2xvA2JmMQR2dGlkA0ZGWFVJMTNfM Q--/RV=2/RE=1427834105/RO=10/RU=https%3a%2f%2fwww.928gt.com%2ft-wallyhvac.aspx/RK=0/RS=BqNWcTrxk4IfnoJysFnRh6M9Z_8-