joshg1001

1) what is up with MB's intepretation of front defroster. i mean on my other cars, i can adjust temp and speed of fan. in the merc, pushing the button instantly turns the heat to max and fan speed to the highest. i mean i used it over the weekend, and it didnt seem to help with the clearing of the windshield. just weird. i remember my 1994 C280 was horrible at defrosting, i mean it didnt do anything. while i havent tested this for sure in my 09, i cant say that im hopeful.

2) also in my other cars, i can turn off the recirc button and air would come through the vents from the car cutting through wind. this would keep the temp of the car perfect. but you cant seem to do this in the merc. anybody find a way around this? or is this something ill just have to accept with buying a merc.

micropower99

Honestly I found this defroster to be the best I've experienced yet. I put it on max windshield defroster and in just a couple seconds (literally less than 5 seconds) the foggy windows are all gone. Sucks that it has to go full blast though.

e1000

1. Lots of other cars run the fan at full blast once you hit the front defroster. If you don't like it, you can always take it off auto and select to direct air to the front windshield at your desired air speed.

2. I think you'll just have to accept this one.

C300Sport

My last two vehicles would blow full blast when you pressed the defrost button. I pretty well always lowered the fan speed manually after pressing the button.

downtowncanada

1) After pressing the front defog button, make sure that the AC is activated automatically and turn off recirc. Even if it's cold outside, turning on AC will still "condition" the air by removing the humidity/dampness, thereby clearing the window. Turning of recirc will also stop recirculating the dampness that is in the cabin, most likely from your body heat, damp clothes, your breath etc.

I'm new to MB as well, so not sure if AC is supposed to come on automatically when you press front defog, but my BMW turns on the AC always automatically when pressing front defog, unless it senses an extremely low temperature (like -20...I'm in Toronto), then it wouldn't bother turning it on, as I guess it realizes that the air is pretty dry and to protect the compressor.

2) As for your second question, I haven't asked MB about this, but I noticed the same "lack of fresh air pressure" when turning off recirc on my BMW. They told me that unlike north american cars that pass air directly from outside into the cabin when recirc is off, BMW send the air through 2 cabin filters (charcoal and HEPA) to remove odor and dust, therefore slowing down the airflow and requiring you to turn up the fan. Maybe something similar with the Benz.

I've noticed it too, and find I have to open the window a bit to get more cool air in the cabin on those days when your getting radiant heat from the sun, but it's cool enough outside for NO aircon.

GateKeeper

I rarely if ever have a fogging problem, I run the car with the AC in the on position at all times, be it winter or summer, did this with my X5, just before my new C350, and I have yet to see the windows fog up, the rear does sometimes, but I just use the rear defrost for that.

nyca

If you don't want that max windshield defog mode, don't press the button. Use the mode switch to direct the airflow under control of the fan speed buttons to the windshield, that will defog the windshield at whatever rate you select.

whiteongrey

If you have a fair chip in the glass, in cold winter temps , max defrost will promote the horrid cracking we all hate - main risk is chips on the lower half.