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Today I turned on my AC for the first time this year and I noticed that the middle vents do not blow. The 2 outer vents seem to blow just fine. But I can't get any air to come out the middle vents. It blows out the top and 2 outside vents. Does anyone have any idea what could be causing this. Even when I cycle through the different air flow positions, it doesn't seem to matter.
this happened to me and i was covered under warranty so i didnt really care to understand the problem but i glimpsed at the service report and i think it mentioned that my evaporator was messed up or something.... has to do with the AC unit (duh) and it sounded pricey... sorry for the bad news.
All squared away, it was a vacuum hose on the intake. I must have tore it when I was cleaning my MAF or changing my filters.
Sorry to bring this back from the dead, but where is this vacuum hose located in relation to the intake, I just installed vip's cold air intake, and my center vents do not work now, Is it the hose attachment located near the firewall on the intake?
Sorry to bring this back from the dead, but where is this vacuum hose located in relation to the intake, I just installed vip's cold air intake, and my center vents do not work now, Is it the hose attachment located near the firewall on the intake?
Any help is greatly appreciated.
I had the same problem. The hose is located about dead center of the firewall on top. It is white and about an eighth of an inch in diameter. You can barely see in the back of my motor in the pic
I had a similar problem of no air flow out of the middle vent of my 1999 CLK320. I found the thin white tube and tracked it to the area next to the coolant hoses that go into the firewall. I was able to pull up the white tube and verify a nick in it. The nick was caused by a mouse that had nested in that area. Prior to my ownership, the car was parked very close to a field. I have great flow out the center vent now !
Here's a photo ...
Last edited by ungermm; Jul 20, 2017 at 09:13 PM.
Reason: photo added
In the picture above, is there a way to find out the part number of the grey connector for the two white tubes? My connector broke and I need a way to connect the two white tubes. Want to fix this before I get in to the rest of the A/C issues. Car is 2001 320CLK.
The vacuum line connector is actually two parts (202 800 02 53 & 202 805 03 44). I think you can also get a elbow replacement from Pelican Parts like this one https://www.pelicanparts.com/catalog...FULEMI_pg4.htm. But, if you don't mind a DIY approach, you can just eliminate the connector with a small rubber hose to bridge the two white tube ends together.
Thanks...seems to go through firewall into passenger foot well area. I did vent test and each vent showed a zero all around yet all are blowing all the time except center not blowing at all.
OK...still problem
here are issues.....all the vents are open except center...can't change them to stop using "flap test" or any other way
I swapped the vacuum lines for #1 and #2 flaps with another ones that were blowing...no change
I pulled the center vent out (lots of fun) and there is nothing coming up to the back of the vent unit.
Does anyone know where the actual flap is behind the dash that allows air to come up to the center? My plan is to manually open the flap and permanently keep it open (open and close the vent on the dash when don't want air from center)
I found what I hope is the problem...found the vacuum reservoir and the vacuum line going through the firewall had a broken fitting at the reservoir ....see pics on this thread... https://mbworld.org/forums/clk-class...ution-box.html
success!!! got a connector for reservoir and voila, center vent blowing AC!!! If you have a center vent AC problem, start at the vent distribution box under glove compartment...I tested it with my mouth to see if suction....if none...trace back to air reservoir hidden behind wheel well (https://mbworld.org/forums/newreply....=714194)...see pics..etc...back to vacuum connection at engine....if any leaks along the way, the vents will all open and middle one stays closed....as soon as vacuum attached to distribution box, they should all operate normally.
Now i understand, all vents are opening, but the midle stay closed if i have leak,when i set it to 9 o clock and back to 3 o clock all the vents are open, i gues i will have to work a litle, thank you very much.
Last edited by Francis Thx; May 19, 2019 at 05:56 PM.
had the same issue where a mouse chew through the white vacuum line used this dorman 47430 the 1/8" to connect the cut hoses together. after connecting the center vents started working but a high pitched squeek or squeel began while driving and pressing on the accelerator it disappears but once slowing down it comes back and its depends on how much of a drop in acceleration happened corelates to the sounds pitch. I am going to see if it is coming from possibly a leak at that soft hose or its collapsing under vacuum pressure. any thoughts on resolving would be helpful.
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