buzz from A/C vents
Thread Starter
Senior Member
Joined: Oct 2011
Posts: 314
Likes: 29
From: Coastal Georgia, USA
2007 E350 Sedan
buzz from A/C vents
I get a background buzz from the vents in my 2007 E350 occasionally. It is not constant, and it does not matter whether the system is heating or cooling or on auto or manual controls. It rises and falls with engine RPM's, and sounds like that noise you get when a car with power steering needs power steering fluid added. It is clearly HVAC related, because it stops when I turn the blower off. When I turn the blower back on, it may or may not resume. The HVAC system works fine-just the intermittent noise.
Any ideas as to what it might be?
Any ideas as to what it might be?
Member
Joined: Nov 2009
Posts: 149
Likes: 1
From: austin, texas, usa
2006 e320 cdi
I get a background buzz from the vents in my 2007 E350 occasionally. It is not constant, and it does not matter whether the system is heating or cooling or on auto or manual controls. It rises and falls with engine RPM's, and sounds like that noise you get when a car with power steering needs power steering fluid added. It is clearly HVAC related, because it stops when I turn the blower off. When I turn the blower back on, it may or may not resume. The HVAC system works fine-just the intermittent noise.
Any ideas as to what it might be?
Any ideas as to what it might be?
Thread Starter
Senior Member
Joined: Oct 2011
Posts: 314
Likes: 29
From: Coastal Georgia, USA
2007 E350 Sedan
common problem. look at post #19 for the fix: https://mbworld.org/forums/e-class-w...er-ac-fan.html
Member
Joined: Nov 2009
Posts: 149
Likes: 1
From: austin, texas, usa
2006 e320 cdi
I thought someone mentioned it in earlier post, or another posting. I can't remember. I presume that can happen - the voltage from the alternator goes up with engine RPM, and that would increase the electricity to the fan. I suppose somebody may want to correct me that there is a voltage regulator in between. But regulator tries to regulate in a tighter range, it's still a range, not a fixed voltage.
