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Well, than it sux. Why can't they fix it? Who wants to smell a car ahead of you? It's also a huge health concern.
It's not necessarily "broken"
I'm not exactly sure why they do this, but my guess is to get some fresh air into the cabin every once in a while so you're not breathing the carbon monoxide you breathed out. Again, just my guess.
Where are you driving where you're constantly getting in bad fumes from the car in front? I usually just ignore the air recirc. button and I never notice any bad odors or anything.
I'm not exactly sure why they do this, but my guess is to get some fresh air into the cabin every once in a while so you're not breathing the carbon monoxide you breathed out. Again, just my guess.
"Carbon monoxide you breath out", was that supposed to be carbon dioxide because people do not breath out carbon monoxide.
Anyhow, the recirculation button is one of the best buttons in my other car (subaru legacy). In Australia there are LPG powered cars and they smell horrible. I can't wait to see what my new ML300 does.
The cabin filter should pretty much remove diesel smell from air entering the vehicle. Maybe you need a new one. Many dealers sell two types, one cheap and one expensive. The cheap one won't remove the smell.
As for locking into Recirc, can't be done and should not be done. Returns to normal mode to avoid sufficating the occupants. If you are still behind a smeely vehicle you can reset it to recirc when it returns to normal.
QUOTE My problem is that the exhaust smoke from cars in front me gets inside of my 2008 ML350. I hate that exhaust smell.
The climate control recirculation button can prevent from it only temporarily. After a short while it turns itself off.
Would anybody know if the recirculation button could be permanently locked in the "on" (lid) position?
thank you
If you hit the button once, it would close the cabin fresh air intake. If you press and hold it for about 3 seconds, it will CLOSE the sunroof and every windows which were open, whole or just a little bit. Totally recirculate the cabin air. It would hold like that until you hit and hold the Recir button again about 3 seconds, it will REOPEN the air intake, the sunroof and every windows to their EXACT positions before closing, half-way or just a quarter. It does have memory about the windows positions. C'est merveilleux, only MB has.
It's not permanently thou, but you can control the air circulation at will.
I fixed the broken Recirculate Botton from turning off....but the fix is not for the average DIY. It's not that hard, it's tedious.
Also, if you that guy (gal) who thinks that Mercedes knows better and that turning it off periodically is best...go poop in your hat...this isn't for you.
Here is what I did:
I purchased three electronic boards. The first board (postage stamp-sized) is a DC-DC Buck Step Down board ($1). Lowers the voltage from 12 to 6V. Next is the Arduino Nano clone ($4). Runs a modified C++ language. The program is a total of 28 lines of code. It drives the third board 5V Relay board, High/Low Trigger ($2.50). I am using it as a momentary switch here, programmed at 500msec (I can shorten this to 100msec I think). Presently there is a 3.5-second delay between when Merceded turns the recirculate function off and I turn it back on. I can and will shorten this delay with the next program update. The program also has a built in 5 second delay at startup to allow me to fire the glow plugs (it's a diesel, but can be removed for a gas car). They take a max of 3.5 sec at 0ºF, so I could trim a second off here too
The install, remove the heater control. (there is a good video on YouTube that walks you through it. Locate the Recirculate switch and solder two 24-28 gauge wires to it, and run these to the location of the Arduino nano. I installed a shelf in my glove box and placed it there. I still need to cover the wires,,,
AAA Battery for Scale. Box is 1.1 Inch high Where the FIX resides. That's the recirculate switch (top right) The wire installed with a strain relief and run to the glove box
10-17-2009, 02:25 AM
