Every now and then there is a sorta buzzing noise (sounds like I got a dragonfly trapped in there) coming from behind the center vents or there abouts. I have figured out it comes on when I turn on my headlights, but will go away if I turn my fan speed **** to a different level, not the same one every time just different than the one that it is currently at and this is with out the climate control being on. It will also go away if I just move the slider over and turn the climate control on.

Any ideas, before I start pulling the center console apart?


Thanks,

 

Dave,

The noise sounds like a failing diaphragm controller - there's one just below and to the pass side of the center vent. Or it could be something loose and buzzing, hard to tell without the car in front of me.

If the electrical component is not a red herring, it could also be one of the electrically actuated vacuum switches on the trans hump. Remove the side panel on either side of the console, see if you can track the noise from there.

The MityVac is the easy way to diagnose failing diaphragms, if you have the manuals, 'tis relatively straightforward from there.

Greg

 

Greg,

Although, I don't know what those things are that you mention, I'm sure I can find them once I get the panels off and considering the noise is pretty loud, it will be easy to find since I have an idea where to look.

Do you have any idea why turning on the headlights would activate this noise, because during the daytime when the headlights aren't in use, I never hear it?

Thanks for the starting point. I will pull those side panels off first and see if I can narrow this down. I have been wanting to pick up one of those MityVac setups for a while now and this just maybe the problem that gets me down to harbor freight tools to get one. (Man, I love that place)

Thanks again,

 

my car does this, not allways, just sometimes and the pitch changes inversely to the amount of throttle opening. not so bad at the moment so im not diving in there but at one point it was really loud and driving me nuts!

 

Thanks Nick, that defiantely sounds like a Vaccume related issue.

 

Dave,

Oversimplifying a bit, but.... engine vacuum is used to control movement of vacuum servo diaphragm levers that open and close various vent doors in the HVAC system.

The engine vacuum is fed in on a long line that you should be able to see when you remove the console side panel on the driver side.

The vacuum is then fed to a "block" of electro/pneumatic switches that the climate controller electrically actuates to allow vacuum to flow to the desired diapragm servo to open/close a door.

You can check individual diaphragms from this vacuum block using a MityVac.

As with all things vacuum, don't suck it down too hard - if you get vacuum and hold it on a coupla/few pumps, don't risk damaging a diaphragm by seeing "how much it can take".

If one of those electrically operated valves has a leak near it, operates a leaky servo, or just ain't quite right - you can get noise from them.

HTH,

Greg

 

Listin closely at the intake of the temp sensor on the dash.

 

The vacuum actuators go bad. I just fixed one and have another bad one. I can't see a relationship between the headlights and the vacuum actuators though. I'd do some more investigation before pulling out the cenre console.

 

Mark,

Yup, they definately do go bad - and oddly enough they seem to have a higher failure rate on the later cars - don't know why.

But you don't have to pull the console to diagnose (or most times) replace them - you just have to unscrew the side panels between the tunnel and the console.

Greg

 

Thanks for all the suggestions guys. I haven't had the time to investigate this further, due to work, but am hoping to get a chance Tuesday and I will report back. I am going to get started by pulling the sides off the console and work my way from there.

Thanks again for all the help,

 

If memory serves...
Greg and Arron have you pointed in the right direction.
Nicole had a similar problem about two years ago and she did track the problem down and fix it. Maybe she'll post and give you the skinny on the cure. I think she had an additional and or a related HVAC problem with the controller head and she had to replace the 'Slider" as well.

 

I don't specifically remember the buzzing sound, to be honest, but think it might have happened when I had vacuum leaks in my system.

I do remember that one of the flaps in my HVAC system kept moving every time I stopped at a light, and again when I took off. In high altitudes, this would happen even more often. It was a sign that there was a vacuum leak somewhere.

I took my center console out and replaced the diaphragms, as well as the rubber manifold at the solenoids - it had become hard and wasn't sealing anymore.

There were a few other vacuum leaks, some of which docmirror helped me track down. One I remember was at the vacuum splitter next to the brake booster, and another where the vacuum line enters the reservoir in the driver side wheel well.

My recommendation would be to get a MightyVac and start checking vacuum. Start at the splitter at the brake booster, and work your way further from there.

Hope this helps!

 

I think the noise could be caused by the critter in his avatar.

Or, the critter's great, great ....great grandchildren at this point in time.

 

So, has anyone had the same problem, small buzz sound that varies with RPM.
I changed the two center diaphragms and put the center console back. Ash tray and side carpet covers are still off and the buzz sound seems to be coming from the hole the ash tray mounts to.