W126 interior temperature sensor
 

First, my 420SEL has an interior temperature sensor located overhead next to the dome light - correct? Lately a squeek has started in the vicinity of the sensor, beginning as soon as I start the engine.... is there a tiny fan associated with the temperature sensor? The squeek sounds like a tiny bearing going bad, and is driving me crazy. I have looked in various parts catalogues, including fastlane, and can't find a fan associated with the temperature sensor. I recall a discussion in forum a year or so ago regarding such a fan, and I searched with various key words...but couldn't come up with anything. What else in the overhead dome light structure could cause such a squeek? Hint - the squeek goes away when I put my hand over the temperature sensor opening......

JoeB

Perform a search at this site for "little electric motor/fan behind the dash"

Your problem could be the sampler blower motor, however that tiny motor is located either behind the glove box or, if you have air bags, above the passenger side footwell. Whether that sound can travel from the faulty motor, through the aspirating tube, to the sampling port near the dome light is a bit of a stretch....but, who knows?

The little fan you are looking for is called the aspirator motor, and it blows air through one of the air vents up to the sensor near the dome light.

On W202's and W124's, the aspirator motor is inside the passenger air vent next to the glove box.

I'm pretty certain this is the cause of your squeak.

I did a quick search for "aspirator" and found a bunch of responses. I usually struggle with the search function, but this time it worked for me. It seems everything is buried in the archives somewhere.

Mike Tangas posted this for W126's:

"Open and empty glove box. Remove the centers from the seven "plugs", then pull the plugs. Disconnect the glove box light and remove the glove box liner (it will take a bit of tugging - tight fit). Once the liner is out, you'll see the sampler blower just behind the vent. One hose and one two pin connector. The blower just snaps into a mount.

Word of caution, it is easy access but a tight fit depending on hand size. I had to use two hands to reconnect the hose and found I drew a little blood on the back of my hand, where it rubbed against the sharp edge of the glove box opening."

Suginami, thanks!

I did a quick search for "aspirator" and found a bunch of responses. I usually struggle with the search function, but this time it worked for me. It seems everything is buried in the archives somewhere.

Mike Tangas posted this for W126's:

"Open and empty glove box. Remove the centers from the seven "plugs", then pull the plugs. Disconnect the glove box light and remove the glove box liner (it will take a bit of tugging - tight fit). Once the liner is out, you'll see the sampler blower just behind the vent. One hose and one two pin connector. The blower just snaps into a mount.

Word of caution, it is easy access but a tight fit depending on hand size. I had to use two hands to reconnect the hose and found I drew a little blood on the back of my hand, where it rubbed against the sharp edge of the glove box opening."

thanks, concur it is a small constant-speed motor - but I need to know exactly where it is in W126 models.....moderators, can you help out?

JoeB

It's directly behind the most right hand air vents and ducts in the dash. Remove glove box.. go right, and you'll feel it. It's the size of a small CPU fan (which makes a fine substitute). Follow Mike Tangas' directions; he never steers us wrong.


Edit: I think the posts are out of sequence with the New Year and the post times are showing from different zones on some of the threads....therefore; I was redundant ;)

I just replaced my motor as the outlet where the hose connects had snapped off at some stage. The DPO had used hotglue and it eventually came apart again. The motor was about $75 US.

Matt

Awwww, thanks Golden :o , and you too Paul!

I think this miniature blower motor is located on top of the passenger kick panel once you remove it. I also have a squeek when I start my car cold for a few seconds and I tracked it down to a noisy transformer near my engine computer. It may not be the aspirator making the noise.

I have a 124 and the motor was making a loud noise. I pulled it and applied some synthetic oil to the busihings several times after drving awhile and the noise has left. This is probably just a temporary fix, but it has lasted thus far.

Ron

oustanding, thanks to all for your replies.

yes, several of the replies were posted out of sequence.....makes for interesting reading....and provides good training for having a discussion with your wife.....

JoeB

would this motor be in a 1983 W126 as well? i dont remember seeing anything like that when i replaced the dashboard........... thanks
Ryan

Hi everybody,
I tried to find the blower but can't. On a 1987 420 SEL (W126) the look to the right after the glovebox is out looks like this:
Where else to look?
Regards
Reinhard Kreutzer

Your kinda in the right spot, but you didn't need to remove your glovebox. You need to remove the lower kick panel, held in by 3 small screws on the top, one plastic screw to the left and one metal screw to the right once you remove the side wall by pulling it twoards you.

Thanks Turbodiesel,
I just looked at the passengerside. In order to get the right side out, it looks like I need to remove the carpet in the footwell. Under the carpet is a black plastic panel, that overlaps the side panel. It
a. has an air-bag warning on not to disconnect a ten-pole connector unless battery is disconnected,
b. seems to be screwed at the bottom to the front.
I take it that has to come out too.
Do I need to disconnect battery or is it still save just to remove that black panel? There is no passenger airbag as far as I know.
Thanks in advance
Reinhard Kreutzer

No need to remove that panel, or the plug. I am taking about the carpet covered duct right above your knees. Sorry if I confused you.

I'm getting confused because I think we're talking about two different fans.

There is an auxilary fan in the kick panel under the dash that Turbodiesel is talking about.

The other fan is the aspirator fan is right directly underneath the passenger air vent, just to the right of the glove box.

I don't know which one is actually making the squeaking noise, but I think it's the aspirator motor fan below the air vent.

Turbodiesel,
I don't think you confused me. It is just that I cannot take the sidewall off in order to get to that screw on the right that holds that "kneepiece". The floorpiece seems to overlap. I 'll try tomorrow with some turning/lifting before I unscrew.

Suginami,
take a look at my photo. It is a shot to the right from where the glovebox used to be. I don't see anything that resembles a fan motor unless it is in that black plastic hose.
Thanks
Reinhard Kreutzer

Mine was in the black plastic hose.

Suginami,
so you push the accordeon-type hose up or down and there it is?
Would have never occured to me to open that up.
I'll give it another try tomorrow.
Thanks
Reinhard Kreutzer

It's been so long that I don't remember.

On second thought, it's not inside the tube, but sort of next to it. I did have to pull off the tube to get to the fan motor.

You just really have to yank at it. Pull it twoards you, it's held in with two clips.

Well, I got it out far enough to take a look at it, but the lower panel seems still to be stuck at the left side, even after I took out 5 screws and a sixth that connects the black plastic panel to it. A look through it reveals this:
I assume that is the fan motor.
Suginami, you can also see it from the glovebox behind the black plastic hose, but it seems to be better to get to from the lower panel.
Turbodiesel, do you just pull or is there a twist to it?
Thanks
Reinhard Kreutzer

Well, in any event, you found it.

That fan in the picture looks like the aspirator motor, although mine is much smaller.

FWIW, Mercedes is making this part smaller and smaller. My mechanic showed me one from a W202 C class, and it was at least half the size as mine.

does anyone know if this motor is present on the early model W126's?????
Ryan

It has to be there on earlier models.

That's the same exact part in my 126 that buzzes for the first 1 minute after cold start up. At a quick glance it looked like a transformer to me.

There is a certain art to taking out that duct, and a real pain in the ass to get back in. It's kind of a puzzle of duct work. It is probably caught on the left side duct, just wrestle with it, it will come out.