AC blows warm on driver and cool on passanger!
 

On my '99 E320, the climate cotrol blows so-so cool on the passenger side, but blows warm on the driver side, when set to LO or 14degree temperature. Which part am I looking at replacing? Thanks a Lot!

Do a search - sounds like your charge may be low...

Your low on refrigerant. You'll need to recharge it and look for leaks.

Warm and cold on different passengers?
 

You have a really modern Mercedes, with selective heat by position in the car!! Perhaps you can sell that system to others?? (Just kidding) BC

Wouldn't that be "zoned climate control?"

Check your heater hot water control valve (duo-valve);solenoid valve which controls the flow to each side of the heating; when faulty it defaults to full flow, probably one side of yours is faulty therefore constant hot flow , to check disconnect power lead at duovalve then both sides should run hot no matter where temp.controls are set.
See here, http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1SL15BCKH1SL15C9I7&year=1998&make=MB&model=E-320-005&category=R&part=ACC+Mono+Valve.
Geo

Thanks Shandy
 

Thanks Shandy for the first input that makes sense. I knew I didn't have a leak or was not low on charge, as my compressor turns and stays on all the time. Other ac guys also suggested the heater valve, i was just looking for re-assurance. I allways ask for multiple opinions. If there is anything else you can think of, please let me know. Thanks again.

Hot & Cold
 

My parents S class did this about two years ago, changed the likely culprit the water valve as mentioned by Shandy. In our case it did not fix it.

The problem was Mom on the passenger side was aiming the cold air away from her and the cold air was blowing onto the temp sensor triggering it to blow warm on her side only.

It probably is the water control valve like Shandy says but check the vent aim first.

What part of our advice regarding charging doesn't make sense? I have personally experienced the issue you described, and it was in fact "cured" by a $7 can of refrigerant from Wal-Mart. Due to the variable displacement design of the A/C system in the 210, the evap can put out a warmer temp to the driver vent if the charge is low. Usually if middle is cool and both outer are warm, it's the duovalve. If warm on driver's side and progressively cooler towards passenger side, it's low refrigerant charge. This is a very, very common problem. Of course it is also entirely possible that the duovalve is bad - if you want to throw more money at the problem be my guest.

I told you to do a search, did you? Well I did - look HERE. This is just one thread - if I had the time to search properly I could come up with 20 or 30 threads that detail this exact problem being caused by a low charge.

You got multiple opinions but only accepted the one you wanted to hear. Why be so quick to discount advice that you asked for? With only 3 posts it's obvious you're new to this forum and I suggest SEARCHING and, above all else, if you're going to ask for advice then it might not hurt to listen to others who have been there done that. Oh, by the way, whatever the fix ends up being, please report back so you can help others in the future who do a search on this topic.

Thanks for the link gmercoleza
 

Thanks for the link gmeroleza, however, the thread you linked me to explains that low charge was NOT the problem.

You are correct, low charge was NOT the problem. But then the problem wasn't exactly like yours, was it? READ IT AGAIN:

Notice, his symptoms were hot/warm air on the outboard vents, nice cold air on the center vent. This is not the same problem you are having. Per your description:

Your symptoms are entirely different. Warm on driver's side, and progressively cooler towards passenger side. You never said anything about cold air on the center vent. Are there some details you haven't told us?

I consider stevebfl to be one of the resident A/C experts. Notice what he says, which backs up what I said:

Notice, he says "I have had the dual heater valve cause the outsdie ducts to be warm." Again, I will repeat: Usually if middle is cool and both outer are warm, it's the duovalve. If warm on driver's side and progressively cooler towards passenger side, it's low refrigerant charge.

It's obvious I'm not gonna convince you. Go ahead and order the valve for $166 + shipping, and let us know if it works.

Dear gmercoleza, obviously I'm gonna check the charge first. If my charge is sufficient, I'll change the duovalve. If my charge is low and after re-charging my probles go away, I will not replace the duovalve obviously. Thanks for your thorough inputs. I will keep you gentlemen posted.

95% of the time when i see this same issue it is low freon, definately start there first.

What now?
 

Dear friends,

I've gauged my AC charge this morning, the reading was over 50psi= full.

Guess I should move on to changing the duovalve?

Connecting a charge hose isn't the answer...have the system discharged & PROPERLY recharged with the correct weight of refrigerant!

50PSI means little OR nothing! a normal system at rest at a temp of 70-80F will read at least 100psi. but again it isn't all about pressure but about correct refrig charge by weight!

YOU description sounds like a LOW charge of R134a not a bad valve!