Thinking that my blower was going bad, I discovered that this little whatchamacallit is what was making all the ugly noises. What is it? It has a tiny blower inside.

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Julio Garcia
1987 300 SDL (mine)
2006 Jeep Liberty CRD (mine/kids)
2008 Hyundai Sonata (wife)
2000 Saturn SL AKA "Gocart" (everyone)

Julio,
I think its the air sampling pump for the climate control.

Thanks John. For what it's worth, the rubber hose seemed constricted when in the clip that held it. It removed it from the clip and the noise may have gone away.

Also, after reading other posts about this part, it looks like it may cause erratic behavior with the blower and AC, which I am seeing. Maybe I should just replace it? After ripping everything to get to the blower, getting to this air sampling pump is pretty easy.

__________________
Julio Garcia
1987 300 SDL (mine)
2006 Jeep Liberty CRD (mine/kids)
2008 Hyundai Sonata (wife)
2000 Saturn SL AKA "Gocart" (everyone)

Julio,
I purchased my first Mercedes about a month ago and am having a blast fixing all the little things on it. The car itself is excellent its just the bells and whistles on it that have the issues. My air sampler pump sounds so funky that I thought it needed an exorist sprinkle water and lay hands on it. lol. Mine sounds like crickets sometimes, grinds loudly when I steer right... its crazy. Haven't got to it yet but when I do Ill let ya know if it can be revived or not. Later Julio, Johnny

Yup, that's the small blower for the climate control temp sniffer. The other end of the tube goes up by the dome light to the small grille.

When you take it apart to oil it do NOT turn the wheel backwards.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Mine used to growl, too. I havent heard a peep out of it since I took it apart and cleaned/lubed it.

I know it's working.

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My first Mercedes Benz. 4/6/07.

1984 190E (201 024) 2.3L four.

I did not pay close attention when I was working on the big blower (what a hassle!), but I thought this rubber hose went to the small vent on the passenger side (???). I was reading the FSM and other posts and got completely turned around. But, what you write makes the most sense. I will take it out next weekend and clean it. I hate to have to get a new one. I am having lost of odd behavior with the HVAC.

1. The defroster vents do not open up, except one time when I was fiddling with the blower. (Might it be a leaky vacum hose?)
2. No heat at HW speeds (monovalve, apparently?)
3. Compressor comes on when the EC button is pushed on (Climate control module? Some of the lights on it don't come on right. I have pulled it out and cleaned it thoroughly with contact cleaner. Auto works quite well)
4. The blower can't seem to make up it's mind when it is not on auto (vacuum hoses again??)

So, I have lots of troubleshooting to do and I am not completely sure where to start eating the elephant. Lot's of post with good information, but I do not have a good attack strategy and I sure do not want to buy parts before I have a better idea of what is wrong.


Suggestions?

__________________
Julio Garcia
1987 300 SDL (mine)
2006 Jeep Liberty CRD (mine/kids)
2008 Hyundai Sonata (wife)
2000 Saturn SL AKA "Gocart" (everyone)