It's $37 at the dealer and even cheaper than that at Parts.com.

BTW success , I took everything apart again and this time I pushed the rubber grommet thru the firewall(?) and over the enginebay hose. This gave me enough leverage to snap the part onto the enginebay hose. So, I put everything back together and took it for a test drive and wah-hoo heat!! how sweet it is

OK, so I just install a new valve. And now I have cold air all way around. Before the front was blowing ok, the sides and rear was problem.
The thing is that i turn the ignition on whith the no valve an open hoses, and I had a refrigerator leak, I dont now how much, bur looks like was a bit. Can it be a problem? and how do I chek the refrigerant level? thank you.

If it's a coolant leak around the valve, did you check for leaks before you reinstalled the molding, wipers etc. If not, I would take it apart again to see where it is coming from. The front enginebay hose would be my guess, unlike the other three hoses it must first snap-in BEFORE before the locking pin is pushed in?.

The other thing is, if your saying that the temperature is different at various vents then that would seem to be an A/C problem (i.e. low on freon)?

So, is it a heating or a cooling problem your are having

So, looks like I was wrong a bit. Refrigerant(freon) goes trought aluminium pipes next to Valve, leak was from the enginbay hose, seems to me to be antifreeze,(green color). I check the hose,that comes from the passager side to the top of the vsalve, and when I squeeze it, it looks empty.
I have the same Temp blowing from any vent, and it's almost like outside temperature, may a bit warmer.

You reconnected the electrical connection to the valve, correct? Easy thing to overlook or not seat correctly.

Yes, I did. and in between I put the old one back, and the old one is blowing hot. and now I have my new one on and it doesn't work again. I will send it back on monday, will ask for a other one. now I have to go put the old one back.,
Thank you

BTW. does anybody know how the coolant level afect the AC ? I mean if the coolant level is low, can it just not blowing hot?

I don't believe that a low coolant level would have any effect on your A/C. You would be getting a warning if your coolant had reached a critical low level that would affect your engine. Sorry to see you have to install and reinstall this valve. My valve was not my problem after I replaced it; it is still my SAM that controls the valve that is not sending the right signal to open and close the valve at times. I'm reluctant to spend the $1,000 to replace the SAM as it's more of a nusance than anything else.

Okay, this sounds like the same problem I had. I could not get the enginebay hose on properly. The enginebay hose has to be pushed really hard and if you do it right you will actually feel it snap into the valve.

Try putting the new valve on again, and this time push the big rubber gromett thru the bodywork and down along the enginebay hose (in other words get it out of your way). Now attach the enginebay hose first (i.e. do not attach any of the other hoses yet), doing it this way should give you enough room/leverage to snap the hose into the valve. Good luck!.

well, I hope my SAM(I don't know what is it) is ok, because old one is blowing hot. Even after I installed old one back it took a while to start blowing hot again, engine was on and I whait before it will reach 90+ degree, before it will star blowing hot again. I think it just has to work a little.

SAM-Signal Acquisition/Activation Module. The driver's side SAM controls this valve operation.STAR diagnostics showed I error codes related to the valve operation from my SAM. I would think that the odds of purchasing a defective valve are fairly remote, but I hope this is the problem in your case.

So, I checked the new valve and it's working. Before I go under the hood once again what should I look for. Is the SAM the the metal parts on the plastic cover on top of the valve? Did any body have such a problem before, maybe there is something else I can look for?
thank you

Hi.Tanks for your great post. I had same problem in my E240 and I changed the valve, but again I have cold air.What should I do? Please Help

I've got the opposite problem, I have an '05 S55 that will only blow hot air, except if I turn it to low or off automatic on the center vents. Therefore, I know that the AC works, but the auto setting only blows hot air. I have to turn the system on and off to regulate the temperature at a normal level. Any suggestions?

I swapped this out today and it cured my rear heating problems... Removal was an issue and it's was a PITA to get the clips loose but the install was a piece of cake.

Is it possible that the change over valve can leak water or Coolant and make its way to short out elec. system? My 2004 e-500 was blowing cold air instead of hot(I had the change over valve changed on another MB) and before I brought it in for repair it began to work correctly. After all the snow and rain we were getting my display went haywire showing brake failure,coolant,esp,bas,brake light failure,etc all at once. Now the car will start but I can't get it out of park or turn on any accessories. I'm wondering if the problem is caused by weather or leakage from the change over valve, or something other, any ideas. Thanks

Just had my change over valve replaced, went to pick up car and was told the ECU had failed, it had water in the unit, could this water have come from fitting of this valve

just had my change over valve replaced, went to pick up car and was told the ECU had failed, it had water in the unit, could this water have come fromfitting the valve

Did this on my '05 E500 4Matic in about 45 minutes. Fixed my rear heater blast problem.

Removal of the wiper motor assembly is the key to making this a snap. I used vise grips on the factory clamp, used the hanger trick, removed the big crommet on the engine firewall, and left the retainers down when re-installing - easy fix due to the excellent info and pictures in this thread.

A211-832-05-84 was in-stock at the dealer - $51 with MBCA discount. From getting the part to installation and testing took a total of an 75 minutes.

The new valve "-05-" has what looks like a filtered breather hole for the motor compartment of this valve. The hole is shrouded for protection from above on the outside of the casing. I opened up the old "-00-" valve and confirmed water inside the compartment and corrosion on the motor and internal electrical contacts.

Thanks to all who posted here for this fix. If I include problem indentification, searching on this forum, getting the part (including travel time) and installation, I only spent 90 minutes max on this fix! Only possible because of those that have taken the time to post here. Again, my thanks!

Awesome write up. Definitely saved me lots of time and $. A few things I would like to add for other folks going to attempt this repair themselves.

I found the part for only $30 at getmercedesparts.com which is MB of Annapolis, MD.

The 3 screws to remove that electrical box are t20 not t25.

A standard hook and pick set like pictured here >> http://www.craftsman.com/shc/s/p_101...4&blockType=L4 is all that's needed to remove all the clips. This is an item that should be in everyones toolbox.

After you install the new valve and before you re install the shroud be sure to rinse underneath the valve to wash out the coolant that leaked on to the paint.

Finally clean the bottom of the windshield underneath the shroud. My glass had some dirt buildup. Also be sure to clean underneath the rubber seal/ lip that sits on the glass. Their tends to be buildup that gets in between the glass and the seal. This will ensure a nice tight seal and help keep dirt out.

Here is inside my defective unit:

Does this apply to 2002 S430? I called the dealer for the part and I was told the part # is 220 830 00 84. Did I ask for the wrong part? According to the dealer, the part is around $250 and it includes auxiliary water pump.

Like all others who posted, this was an excellent post by w211ryda! I followed his and many of the other suggestions, and was able to complete this operation. My problem was excessively hot air coming from the rear vents even though the front AC was normal.
Now I need to replace the windshield trim/cowl that had to be removed to access the windshield wiper mechanism and the defective part. The plastic section is in ok shape, but the rubber trim that presses/seals on the lower portion of the windshield is cracked all over the place. It was showing cracks even before I did this repair, and now it has sections that are broken off.
Would greatly appreciate anyone's input as to what the part number is and where best to get. I'm sure I can drive to the stealer, but wanted to check on-line first.
Thanks to ryda and everyone else that posted their secrets on this thread!
Tom

Found the part and part number. For those who will have to replace the trim cowl, it's part number W211 2118300013.
I only found it at one place on-line and it was the same price as the local stealer - $156.

Wow you got raped. You didn't try the website I posted? https://www.getmercedesparts.com/oem...des-parts.html It's only $97.00.

Hello on my 2006 e320 CDI at 80 outside when I press the auto on the climate control set at 68 the system will blow hot air for about 1 to 2 minutes from the vents under the dash and the side vents then will cool and everything is fine but if I turn off the car for 5 or 10 minutes the same hot air routine then all is well.I put my gauges on the freon and got 30 psi low side 200 high side seems about normal is it the change over valve and does the CDI have the same setup thank you Don

Hello new to Mb forum and I just want to say Thanks for posting such a great write up on changing the valve for the heat and ac control. i just finished up and it works beautifully