southernjim

Is anyone else having issues with the windshield fogging on the outside? Every morning (outside temps around 70 deg. F) the windshield, at the bottom just to either side of the triangular shaped speaker in the middle of the dash, continually gets condensation on the outside. I usually leave the A/C unit on Auto, but have tried adjusting the fan away from the windshield vents and still have the problem.
I have the 230K sedan which does not have the digital climate control system. When in AUTO mode, the fan directional knob (on the right) does not control the location of air, correct? Even when I have switched off the AUTO button and adjusted the fan location to feet, the windshield continues to fog up on the outside. If anyone else has this issue, have you found a way to cure this problem?

Jim Banville

To keep my windshield from fogging, I turn the actual vent control wheel on the uppermost dash vent to the CLOSED position and I also turn the vent control wheel (with blue markings instead of white markings) in the middle of the center air vents in the CLOSED position.

MarkL

I have that issue too, but it doesn't usually cause much of a problem except in very humid weather. I'm not sure adjusting the upper dash vent will solve it totally since I believe some amount of air is always bled from the defrost vents and that's where the condensation spots seem to occur in my car. I just do a single wipe w/ the wipers occasionally if it's a problem.

JimB

as of now as a week old owner of C320 S/S I haven't figure it out yet how to get rid that fog, but I sure will try Jim Banville suggestion Pretty happy owner so far....Knock on wood

EDC320

There is actually a note on this in the owners manual (the one thing no one ever reads). It provides the same advice, close the top vent (top of dashboard) and switch the air flow outlet dial from auto to center outlets or between center and floor outlets. The climate control will still function on automatic for purposes other than air outlet selection.
Good Luck with your new car.

session

Looks like you need to change your sig!

revstriker

This is exactly what I did. Works like a charm...

ViKTORiOUS

Wasnt there a problem with that vent? My C320 was sent back to get a new part for the center vent due to fogging. IDK if its the same as what you guys are talking about, because i experienced the same thing last night on my way back from the Y. I just used my wiper, but it was annoying. Anyone else get the center vent part replaced for free?

mctwin2kman

Mine does that if I leave it on auto. It is caused by the auto selecting the windshield defrost mode on mine and I just turn my climate control to the vents and select a fan speed. I do not have the dash vent to close so I am basically screwed. It is due to the cold air coming out of my defrost vents and the warm air outside. Wiping the wipers clears it but it comes right back so I got sick of fighting it. One reason I am not a big fan of Auto, since it selects the vents for you and sometimes it is just wrong.

JimB

I know I have to update my sig, but where do I go to change it

amdeutsch

Ok, which MY03 sedans still have that control wheel for the top of the dashboard vent? Wasn't that phased out in all but the very early production MY03s?

2~s0L~t

don't trip. go to the top of the screen where there all all those buttons u can click on. click the first one, the one that reads, "user cp." then click on "edit profile" button. u can change ur sig there and even add an avatar. make sure to choose a good one, nice and original LOL.

hope this helps.

JimB

Sig. Modidfied, Thanks...

and big picture removed, sorry

revstriker

Thats a large picture in your sig. Be prepared for some complaints from the 56K users.....

MarkL

The change-out of the center vent was to correct the other type of fogging, or "out gassing" caused by the vinyl and plastic parts. This guy is talking about fogging caused by actual condensation caused by the cold air flowing from the defrost (and maybe center vent) against a warm windshield...

southernjim

Thanks folks, tomorrow morning I'll try cutting off the auto button before the windshield has a chance to fog up, and move the directional knob to between middle vents and floor vents. I tried that this morning, but not until after the windshield had gotten fogged and I might not have given it enough time to correct itself temperature wise before giving up and going back into auto mode.
The earlier poster is correct, my MY03 sedan does not have a vent shut off knob located at the top of the dash board.

MarkL

The only problem w/ this solution is, for the C230/240, putting the system in manual mode will also disable the auto fan. The C320 has separate "auto" controls for air direction vs. fan speed. Since the fogging probably only happens in certain situations, you might want to default to "auto" -- the system works really well that way, IMO. If you notice, air distribution in auto mode goes through different subtle changes keeping the cabin comfortable. Personally, I'd only go to manual mode in the few cases where the condensation really bothered me...

southernjim

Thanks MarkL, that is my plan, leave it in auto mode unless the windshield starts to fog, then switch the air flow around manually.

champa

I have the same issue on my '02 C240, I complained about it and they changed some vent in the dash. But now I know it had nothing to do with the fogging I was complaining about. In the mean time my car still fogs from buttom side of the windshield, but the loaner '03 C230 I got didn't got fogged when in AUTO mode. They both have the analog basic climate control unit. DO the Climatronic unit allow one to select vent direction while on AUTO mode? anyone?, this could be a solution if so, cause the humidity in Florida is no fun. (the windshield fogs creates enough condensation to use the wipers, the I go for a single wiper pass and all the bugs remains get spread all over )

southernjim

This thread has helped me solve the problem. By cutting off the AUTO function and operating the air conditioner through the fan speed and vent distribution knobs I no longer get the condensation at the bottom of the windshield. I just leave my fan speed on setting "3" and the air distribution knob on the "face" setting. This way, all I ever have to do is turn the AUTO button off and on to solve the fogging issue. Thanks!

KOMPRESSORnSC

Butcha' know what? You shouldn't have to do this! I mean, jeez, can't MB come up with a solution so you can use the features on the car without problems? I had a heated argument with my Service Manager on this issue, and of course his solution was to use the manual mode or the wipers. I hate using the wipers becasue of the bug smears and dirt that gets spread around, and I really think that I shoud be able to use 'auto ' mode!

If you notice the posts on this thread, most of us are in the South. For those of you in non-humid areas, you can't understand what a PITA this is. Mine will get so bad that I have to use the wipers before I switch lanes to make sure there isn't a car off my right front fender.

Jim Banville

It may seem severe, but if I was bound and determined to use the AUTO function (which I never do, by the way) and I was getting fogging due to not being able to turn off the air going to the triangular upper dash vent, I'd pull off the cover and see what I could do about blocking the vent. It could be as simple as using some silicone to "glue" a small piece of black plastic to the duct opening.

KOMPRESSORnSC, your car doesn't have rotary dial (in the center of the "face vents") with with blue markings? Of does your car lack the rotatry dial on the triangular upper dash vent itself?

champa

It is not the triangular piece, my car has both the blue dial in the center dash and the dial in the triangular piece. The triangular piece is greate for getting fresh air all over the front when the car has been parked outside. I love this feature and don't mind reaching and closing the triangular vent. Our problem is not with thie triangular vent, but with the defrosting/defogging vent at the buttom of the windshield. In auto mode it always allows some air to go by, and so with our high humidity here in the south it fogs up. If I was to glue something in there, I would completely loose the ability to defrost/defog the windshild in the morning or when the inside of the windshield fogs up in the winter months. In addition I have driven more than one C-class that does not have this problem, and shuts all air to those vents when in auto.

Jim Banville

Okay. Perhaps you should look at getting a digital climatronic unit. I believe you can set fan speed and vent directions when in AUTO mode with that unit, but you should ask some people with the unit.

nrl1

This is not the first time that this issue has surfaced here. There is a design problem but not with the center vent -- but with the defrost outlets when the system is in the "auto" mode.
The solution is to turn off the auto and make sure that you are directing the air to the side and front vents only. Then again you can take it to the dealer and they will correct it -- as they did mine.