ViKTORiOUS

I have a 2001 C320 and when im driving there is always condesation of some sort in the center/lower part of the windshield, it is so annoying, it wont go away, i always have to use my window defrosters to get rid of it (atleast 60%) but there is still reminents of it, even if the car hasnt been driven. is there a defect i should know about? i havent taken the car to dealership concerning this problem... anyone else experience this? thanks!

20FHK02

The 2002 C Class has similar problem regarding center vent fogging and there is a fix for it. My dealer changed something in the center vent and it does help a lot. I'm not sure for the 2001 though...

vadim

TRy closing the center vent that blows air at the windshield. I keep mine closed at all times, and no condensation.

TimmyC230boy

i have found that putting rainX on the INSIDE of the windshield not only prevents condensation but also helps the windshield not to get as "filmy" as before

ViKTORiOUS

Awesome! Thanks guys! Ill try the RainX, if it doesnt work, ill take it to the dealer... do you know how much it costed to you get it fixed? or was it free?

Buellwinkle

It's TSB, check with the National Highway Traffic Safety website, it will have it there.

todd

Ya, this actually works way better than using Rain X anti fog on the inside. That stuff seems to end up as a filmy coating later on.

MarkL

I think the fogging and condensation are two different "problems". The first causes a film on the windshield from outgassing (!) from the vinyl and other parts of the car. This is the subject of the tech bulletin which involves the replacement of the center vent. Condensation is caused when cool air meets a humid surface and causes the formation of water droplets. I don't think this is covered by a service bulletin.

I've noticed some amount of condensation on the lower part of my windshield in humid weather. Sometimes there is one spot in the middle which coincides with the top center dash vent. Other times there are two strips which correspond to the 2 defroster vents. Depending on the mode of the climate control system, small amounts of cool air may be directed to these vents and I'm pretty sure this is the cause of the condensation. For me, it's on the outside and if I do a single wipe w/ the wipers, it goes away (for awhile). Usually it's not severe enough to cause a real problem...

tberry

Yeah this was on the service bulletin. Even if you have the center vent completely closed it still happens. I'd have to take mine into dealer some day...

revstriker

I had the same problem. I found that when I leave the vent selection on automatic, this would happen. By switching this to manual, I could then choose halfway between the floor and the dash, and I stopped getting the condensation. You can still leave the fan control on auto when you do this. I'm not sure if this will work with the C230/C240 HVAC.

ViKTORiOUS

how do i do this? switching it to manual?

Rainers

I have a 2001 C-Class and MB replaced my center vent yesterday.

I have not noticed any fogging since. Your MB rep should know what the replacement # is for it, and yes it is covered under Warranty.

Becuse of brake squealing, MB also updated my brake pads after bringing the car in 3 times to get the rotors and pads cleaned since new. They said I was out of the adjustment period but since this has been an on/off going problem since week one they replaced the pads with the updated ones under warranty also.

viper

Don't be to sure to say your vent was replaced. My dealer told me that they have been instructed to install some cheap plastic baffle in the vent system so that you cannot re-direct the air toward the windshield. You will also notice that the 2003 C-class models no longer have a knob on the vent. This solved the problem once and for all.

young

just to reiterate MarkL's point...

my center vent was replaced and the fogging is gone. but i still get condensate on humid days. i'll try rev's manual setting

revstriker

From full automatic mode, all you need to do is move the knobs to where you want the air (I put it half way between floor and dash). When in Automatic mode, there is no back lighting behind the switch indicators. As soon as you move the dial, it takes it out of auto mode, and the indicators light up. You have to do this to both sides. The "Auto" indicator should still be present in the fan speed delay, so the auto temperature and fan should still work. (This is for the HVAC that comes standard in the C320. I'm not sure how to do this with the C230/C240 standard HVAC).

young

the c230k is analog (except for those that upgraded to the digital climatronics...). first, you have to press the Auto button (so that the indicator light is off). then open up the magazine, and start waving it gently so that the air flows towards your face. adjust as required.

revstriker

Ah yes, pretty clever. I supposed a thicker magazine like Playboy would work better than a thin magazine such as Newsweek....

young

i personally use "el croquis"...

Odont

I had the dealer perform the tech. bull. on the window fogging and it's no longer a problem!

ROBERT

I have been struggling with the same issue since the moment I picked up my C320 from the dealer 1-1/2 years ago. I remember when I picked up my vehicle and the salesman was in showing me the ropes before I left the lot, and I asked him what the condensation was on the windshield and he said oh, it's nothing....just adjust the vent. The center vent being on or off, or any other adjustment with the environmental controls, doesn't make any difference...I've spent hours upon hours being aggravated by this problem. It is obviously a serious design flaw. Just thought I would share.
Bob...also in Northern New Jersey.

RBinWeHo

I reported the windshield fogging issue when I brought in my '02 C240 sedan (2300 miles) for other service to Beverly Hills Mercedes. When I picked it up, the service writer said that they pulled the center vent, but realized I had that latest version, so it was put right back in.

When I pressed further, suggesting that based on their action, nothing has been fixed - they suggested that nothing was broken. Here's what they wrote on the invoice:

"Windshield is fogging up...NV. Performed A/C Function test. Check version coding. Perform normalizing of A/C motors. R&R center vent on top of dash to check part #, foundupdated part is already in vehicle."

My windsheild continues to fog up. It's frustrating that the service (?) folks either think so little of their product and/or their customers, that they can't just tell the truth and say "A lot of people have the same complaint, we can't figure it out either, just set your A/C system to XX and it won't fog." Oh well.

MarkL

Sorry, but I think some of you guys are still addressing two different problems with two different possible solutions.

When I hear of "fogging" I think of 2 things in the context of our MB discussions. First is the overall buildup of "gunk" on the windshield from the vinyl components of the car -- this happens on most vehicles to varying degrees. This fogging is not related to any weather condition or A/C operational characteristics. You just clean it off every so often. I believe the replacement of the center dash vent has been said to alleviate this problem as it is sealed and doesn't allow the user to push air through the vent so it lessens the amount of "gunk" coming from the vent.

The other type of fogging is the kind you get on a humid day if the A/C compressor is not engaged and/or no dehumidifed air is directed toward the windshield. This is definitely weather related. Usually it is solved by turning on the windshield defroster. In normal operation, a small amount of air is always directed toward the windshield in "auto" mode to help keep the windshield clear.

Now, for the condensation. This is different from fogging. It is the formation of small water droplets on the surface of the windshield, usually caused by cold air blowing on a warm windshield on a humid day. I've noticed this on occasion with my car, but I don't consider it a serious problem. It is caused by a law of physics due to cold air blowing from the upper windshield defrost vents, and possibly the center vent if it is opened. I have noticed that my climate control tends to blow slightly overcooled air through these vents at times when I would have thought the temperature would have been modulated toward a warmer setting, and I think this is the source of the problem. I just do a single wipe with the wipers to clear it away if necessary. Also, closing the upper center dash vent will avoid the condensate spot in the center of the dash.

I'm not sure what the talk of "serious design flaws" is. Not even MB can change the laws of physics. Are you guys getting large areas of condensation, or just small areas above the defrost vents? And, does it only happen on humid days? If it is really a problem for you, then I think you can manually set the air direction on the days when this occurs, by setting it to the upper or lower vents as desired thereby avoiding the normal slight air directed toward the windshield. Just my $.02

todd

Well said MarkL.

Thanks.

BrabusCClass

I have a slight fogging on the bottom part of my front windshield in the center only at night usually when it is very cold. Wiping does not work, nor does the vents (cold and hot), nor does the wipers. I have tried everything and so I just ignore it. After about 30 min to 1 hour it goes away.

Any suggestions?