Mystery Hose

[Meister]

Hi folks!
This is my first post on this site although I have used the site for information for some time.

I have discovered a hose under the glove box of my '83 300D which is detached on one end. It is about the same size as compressor hose (see pic). It is semi-ridgid and has vacuum when the compressor is engaged. If anyone has any ideas, please post. Thanks, Brian

[sailor15015]

Isn't that the supply hose for the cabin air temp sensor? If so, it looks like you're missing the foam piece that connects it and the sensor on the dash. I just used some foam pipe insulation to replace the original foam on my car because it was crumbing.

[JimFreeh]

Originally Posted by sailor15015

Isn't that the supply hose for the cabin air temp sensor? If so, it looks like you're missing the foam piece that connects it and the sensor on the dash. I just used some foam pipe insulation to replace the original foam on my car because it was crumbing.

I agree, make sure it's got the foam connection.

Jim

[rg2098]

Sailor is right. If you look back towards the left you will see a fitting directly below that little grill in the middle of the dash. What happens, is the foam connecter piece turns into dust.

The little grill covers an air temp sensor. In order to get a accurate realtime number, Mercedes uses that hose to draw air across the sensor. Otherwise it would be reading the same stagnant air that happens to waft past the sensor.

[Meister]

Thank you all for the quick responses. When I discovered this hose I suspected what you have told me, i.e., that it is a sampling hose. However, a couple of things bothered me:

1) The hose is large and relatively heavy.
2) The hose has no bends and doesn't seem to have an obvious "path" to go north to the sampling vent on the dash.

What does the connector look like? Where will I find it (or where it's supposed to be located?)

Brian

[Cervan]

heavy?... might be a a/c expansion valve hose...

[Meister]

I don't know anything about expansion hoses. I am more inclined to go with the aspiration hose argument. I would really like to know more about the foam connector. What does it look like? Where does it attach? Thanks

[Meister]

Anyone?

[sailor15015]

Look just above your center vents, between the two of them. On this area of the dash you'll see a little 1" by 1" square with vents in it. Attached to this little square, underneath the dash is an L-shaped tube that comes down and goes to the right. Its connected to the house you have pictured by a piece of foam that, over time, disintegrates.

Basically, stick your face in that hole where the glove box should be, look left, and you should see another hose with nothing connected two it. Attach two said hoses with something of an equivalent diameter (foam pipe insulation, rubber hose, etc.) and you're good to go. I bet your climate control will function a lot better with those hoses connected.

[dmorrison]

That is your air sensor hose. The right end of the hose is connected to the fan base so it draws air over the sensor in the center of the dash. It is connected to the sensor by a foam tube. I replaced mine with a plastic tube.
See the attached post for information.

AC temp sensor FOAM tube??

Dave