I own a 2001 MGM. Recently the air conditioner has started making a whistling sound. The noise seems to be coming from the control panel, but not sure. When I press the off button, the sound changes tone, and then quickly dies off.

Any ideas will be greatly appreciated.

Sounds like a definate vaccuum leak. Are you able to pull the HVAC control panel?

No I haven''t tried to pull it off yet. I figured I was going to have to that at some point. Any idea where I can find a detailed diagram of this area of the dash?

Check the simple things first. I once developed a nasty whistle when I had it on max a/c. Turns out I had sucked up a wal-mart sack into the blend door and it was restricting the blower.

Might be worth your time to stick your head up under the passenger side dash to make sure it''s clear.

Not off the top of my head, but I will see what I can find. If you are any good at "surfing the web", I''m sure you can find a HVAC vaccuum schematic somewhere. I am a little web browsing impaired. Let me know.

I''m going along with the idea that maybe something got sucked up into the blend door. I''ll take a look later this afternoon. If I understand correctly, I should be able to see the blend doorunder the passenger side dash?


Also, any one have any idea how I remove the trim around the air-conditioner controls? The plastic they used on the dash trim is as soft as butter, and I hate to thrash my interior over some stupid mistake I make.


Any information will be appreciated.

Normally yes. I haven''t seen under the dash of an 01, so I don''t know what all would be in the way to obstruct your view.....but it should be obvious when you get under there. If you have the vehicle''s engine running, you can cycle between max A/C and OFF and watch the blend door operate. Should not be difficult to tell if there is a foreign object present.

Look for the edges of the finish panel around the controls. It has push pin type connectors and just snaps into place. It''s the whole panel....not just the surround of the control head.

After the finish panel is removed you will be able to access the four screws that hold the climate control head in place.

Did ya fix it?

Unfortunately no, I''ve been too busy lately so I have not had a chance to fix it.


I have noticed one other thing, it seems to be vacuum related. Sometimes when I step on the break pedal, it starts making the noise. Or if the noise is already happening, sometimes hitting the break pedal (hard) causes it to stop.


I''m guessing that some small diaphram must have failed inside the AC control unit. Most likely means that I must replace the entire control head.


I guess my next step will be to remove the plastic trim piece, and see if that helps me pin point it any better.


Good news is the noise does not really seem to cause any problems, but I know it should be fixed sooner than later.

Well it makes sense, the brake booster is where a good amount is of vaccuum is used and returned. Check the big-ass hose and plastic ell coming off the booster. Too bad it wasn''t a shopping bag. Keep us informed.