paulybagadonuts

Is there any way to turn down the defrost function on this car?

I'm driving home tonight and it's raining out so I hit the defrost button to clear up the windows.

Is there such a thing as a de fog function somewhere or am I just missing something.

The thing comes on full blast like 100 miles an hour at 90 degrees!!

I hit the fan speed buttons but they don't work in this mode. Am I stupid or am I just missing something?

I do appreciate the auto tempurature controls in the car and all of that but there is something to be said for the old time knobs...

My CRV has a temp and fan speed knob and then choose what mode to put it in heat cool or defrost.

Simple and you have lots of control.

I'm probably missing something but is there any way to control the temperature or air velosity when defogging the windshield??

Thanks in advance

Diesel Benz

The defrost is not supposed to be used all the time, mainly when starting first or a quick defrost if something on the go makes the glasses foggy.

If everything is right on the car, auto should do it. But you should have the A/C on, that is what actually makes the fog go away. If you already had A/C on, perhaps your A/C humidity sensor isn't working properly.

I'm not familiar with an ML but every MB I've owned or tried has had the manual temperature and manual air flow direction control options. Also the fan speed. If you start from auto and are not satisfied with one of the settings, you can increase manually the fan speed (there after it would stay where you put it). Equally you can step up the temperature or the direction of air flow. You just should not start from de-frost.

StapleGun

Seems to be normal operation - mine is the same. Welcome to MB ownership, I like my simple Toyota Tacoma HVAC controls as well.

Diesel Benz

I know what you mean but my claim was that all one should need to do with the MB AC is to push Auto on and leave it there. If there is no malfunction, it should take care of initial defrost too pretty well, even better than the manual defrost in the sense that I would not want the max fan noise in most cases, just some extra speed once the engine has enough heat, and that is what the system does.

A different thing if your personal preferences are for some odd reason completely different from typical. Even here everything should be possible but you may not have "a direct access switch" for every function. MB after all has so many more features that the dash would not have enough room to put a switch or lever for each individual setting. Those settings that are not typically needed every day, can and are hidden to make the dash more organised and to allow easier access to those settings that one might need to use more often.

paulybagadonuts

I usually do always just leave the controlls on auto and turn the temp dial as needed but for some reason the windshield was fogging up last night.

I didn't realize the sensors would be able to detect fog on the windshield... maybe from humidity?

Maybe it was just some adverse conditions or an isolated incident. This is the only time I've noticed it since owning the car for just over a year.

I'll keep an eye out but thank you all for your help. I think I understand it a bit more now and will try to just relax and get used to the car thinking for me.

Guess I'm just not used to being pampered. This is my 1st Luxury vehicle. Guess I'm still on the MB learning curve... not a bad thing.

Thanks for your help.

tbenz

depends on the year, there is a button with an arrow that points up use it to direct air to the windshield, older mls you just need to turn the right dial, the defrost button will always give you full heat and blower, the idea is defrost the windshield as quick as possible for safety

Diesel Benz

I'm not familiar with an ML but since this one is a pretty new car, it must have the humidity sensor at the AC system. It would not be measuring the fog directly at the windscreen but it is intended to control the AC compressor to cool the air just enough to keep the humidity low enough, to avoid windscreen getting foggy.

On the other hand I read somewhere that US cars were programmed for max cooling (and heating afterwards to keep the temperature as adjusted). The humidity sensor would not be needed in this case. The negative side is unnecessary gas consumption from running the compressor harder than needed. I guess less of an issue in the US.

I'm assuming the fogging experience was a specific case, perhaps engine was not warm enough or something, and temporary defrost was in need, but should/could have been switched off once the screen was clear. Even this should not happen often, hope so.