W126 Climate Control - Dashboard Demon
 

My 1991 560SEL with 134K mi. has developed a shrill howl from the passenger's side vents when the car is started cold in the morning. It is particularly noticable when it is a frigid morning. After 1-2 min. it quiets down but there remains a whirring and buzzing coming from behind the region of the passenger's airbag. This sound is at a different pitch and volume from the sound of the blower, and remains even when I press the O button on the climate control console. Is there a little vacuum motor in there that is giving up the ghost?

Thanks for any insights.

Best,

Stu

There is a small pump located just to the right of the glove box liner. It sucks air past the temp sensor. Fortunately, you can get to it easily and lubricate it. Open the glove box and pry up all of the plastic push pins that hold the liner in place. Pry down the front of the light bezel. Now you can slide the liner out and once you get the light bezel opening past the dash, push it back through the hole. VERY EASY. Now you should see the pump at the bottom right of the opening. It has an open impeller and you can drop some oil onto it. I would recommend NOT using WD40, as it will eventually dry out. There is some stuff called Tri-Flo that comes in a small bottle with a long thin plastic straw that lets you precisely position the lube. Worked wonders for me!

Thank you! I will lube it before the weekend and report the results.

-S

he has a 91 560SEL. They have the dual airbag option so how will he get to the pump?

I have the same sound with a 94 E320 when started cold and dual air bags, so I'm eager to hear how to reach the noise maker.
Merry Christmas,
Mark

I have the same problem and also have dual airbags I tried removing alot of the trim but still coudnt find the bugger... any help?