I just checked the handbook, and then a pdf to try and do a search - I can't find what causes the electrically heated front screen element to come on - I'm not that surprised as I believe it always automatically turned itself on when it was properly cold (but the user manual should at least refer to it - and I can't see it in there ?)

Speaking to two owners they never even knew they had it, so never spotted it turn on !!! One of them has also never known the Audio fade feature (on his V12 with every option !!!)

I don't know if all W221s have this front heater feature - but mine did and it was still working after the windscreen was replaced... Its for two benefits... its heats around the parked wiper blades and helps get the edge of the screen warm where the demist seldom reaches... and there's also heat for the night vision camera - to stop misting (these might be two independent heaters - no idea)

Mine has an element that goes all the way around the edge of the front screen with lots around the wipe blades in their parked position and then around the rain light sensor - on mine if the front screen was iced up, at engine start up I always noticed the element heat up fast way before the engine coolant heater had a chance to do anything - I NEVER use the front demist button.... (so I doubt it can be this that switches it and when I try it doesn't work)

it just twigged - this has probably been dead since the same software update broke the flipping Navigation overlay / source Audio Fade issue .......And now realise the ONLY module that was updated that same year by Mercedes, but I never tried to reverse the update is the ONLY module I never felt was connected to the Nav fade, so never replaced or re did its software back to its original - but thinking this week, its certainly about the same time I noticed the front screen heater gave up working on my car

Then when I go digging in weird secret German set up for this module I find -

Parametrierung Wischer
Parametrierung Wischerablagenheizung
SRA

Parametrierung Wischerablagenheizung
Coding Wischerablagenheizung verbaut nicht vorhanden

which google and my acronym list informs me is

Wiper parameterization
Parameterization of the wiper compartment heating
SRA - Headlamp wash/wipe system

Parameterization of the wiper compartment heating
Coding Wiper - parked postion heater not installed

and thus latest suspect for BOTH faults is the Front SAM - I think the idiots never realised the screen was heated and thus might have deleted the code that turned it on when mine was updated in Jan 2019
Does anyone know when their front heater comes in?
And or how to activate it?
and if so do you have software 221442700 or the original 221442100 on your Front SAM 2215451632


.

 

I'm going to keep reminding you - when I spot cold weather patterns popping up till one of you helps me out

• Toronto
  
  2°
• Montreal
  
  -2°
• Calgary
  
  -1°
• Ottawa
  
  1°
• Edmonton
  
  -5°
• Mississauga
  
  2°
• Winnipeg
  
  -7°
• Vancouver
  
  7°
• Quebec
  
  -5°
• Hamilton
  
  2°

 

so - still no takers....

here is what they didn't understand on the heater buttons that might be driving a bug on this screen heating on my car...

early vehicles SW - 221 442 1323 REST plays up (my personal thought its in a canbus argument with the Front SAM)
2007 TIPS they knew but were struggling to fix stating in SW 221 442 2023 code comments under some conditions early fault could return
then I guess a better fix and why there was the second TIPS doc was to install SW 221 442 2623 (BenzNinja just helped me load this version on my car)
then for 2010 MY they came up with 221 902 1102 and claim its OK for older cars too - I had this on my car for 4 years with the later F SAM software and my electrically heated front screen hasn't operated in all that time.

my aftermarket screen by Pilkington to OEM spec for my car (gets the most expensive screen they could make IR tint, night vision, heated wiper bit etc.) shows these elements - whereas on the std car whilst you can SEE the heating working when its frosty you just see a black surround so the placement of these elements doesn't show up...

 

My window sticker claims this feature is standard equipment but I do not have defroster lines like that on mine.

Also something let out the magic smoke on me this morning from the right front of the dash near the base of the glass. I am wondering if it is related to this feature.

 

not confident its STD - where fitted the OEM screen has the lines you just can't see them - until its frosty and working - the photo is off a replacement Pilkington JOKE - elements where its meant to have cut out to allow road toll thingy and a sat nav to get a signal bottom middle of the screen were not noticed when these global muppets copied it

indy near my with posh glass is upset with his V12, even Merc can't supply the one we both had when the car was built - as he points out, cars with IR glass got a mirror like finish all round

 

scary

I had a rear one fail on a Pug - at a repair I'd done with some metallic paint on stuff - worked for a year then one winter the screen went red hot in that corner.... fearing it was going to explode I had the windows open to cool... that idea was probably what cased it to pop - probably should have parked up and got out.....

 

Botus the heat in the window in my 221 S-65 powered up with the defrost the window command via HVAC.

I got a kick out of windshield washer hose with a heating element in it to heat the washer fluid to assist with clearing a frosty window.

 

thanks - I'll have to see if that does it on mine

 

BOTUS, I do not have that feature on my 2012 W221 with 4matic and heated steering wheel, set up for winter but without that feature.

 

that was my post one....

you can see on the std one once you know where to look - but its far harder to see than the replacement one I used in the photo - not sure if its std on mine coz of night vision... these have a heater element to stop it misting up where the camera is. the big lines run around entire screen edge with lots where the wipers are (as you can see on mine)

 

I have a 2007 S600 with night vision but I never noticed any electric heat on the wind screen other than the front defrost button. Never knew it was there! I did hear about how expensive the OEM wind screen with night vision was to replace.

 

Yes it was quite scary. Thought I might lose the car but the smoke subsided and I continued driving.

After looking into it further, this is my best guess as to what happened. Something in the circuit got too hot, smoked, and is now probably an open circuit.

I can verify that the heated park position is not controlled by the front or rear defrost command. It does its own thing. I was able to command it and heard a relay click. My fuse is fine and there is a diagnostic for the relay. With no codes, my relay is fine. I think something just let go. Not coincidentally, I have no melting action where the wipers park. I never really investigated this feature before though.

Anyway the front SAM is still thinking it's in control of the wiper park position heater as I idled the car for 10-20 mins in cold temps (below 20F) and while it was commanded on, I saw no evidence of melting. And while I initially was able to command it on and off and heard a relay, 1) I noticed no increased load via voltage drop or change in engine sound/feel and 2) once it wanted to turn itself on, I was then unable to command it off.

For me this is the best possible scenario because it is probably failed to an open circuit/safe state. I cannot code it off. And I could pull the fuse but it would set an open circuit code (that probably won't bother anyone)...

 

- it can be coded - but not in the English version of events...

Parametrierung Wischerablagenheizung . Parameterization of the wiper compartment heating
Wischerablagenheizung verbaut - vorhanden . Wiper parked postion heater - installed


FYI SRA which translate tools won't heklp you find = Headlamp washer

 

Via DAS?

 

lots and lots of the car can only be properly worked on using Developer mode - where its all written in foreign - I guess we should have shouted louder

or grown ups play with the other tools that require proper skills

 

I coded it off with the Launch x431 Benz easily and verified via DAS that it is actually disabled. The Launch was not able to show the status of the coding for whatever reason. But I agree it looks possible to code via DAS.

 

Danka.

 

$76.01 on Ali Express but maybe a Chinese clone of the Launch X431 (isn't this also a Chinese clone?). I suppose in an AI World a clone of a clone is Kosher.....

 

I think most of us can afford this:
$159 with coupon.

 

I thought I would follow up that my wiper park position heater (or rather the mystery smoke issue that I have deduced was the heater frying itself somehow) has not released additional smoke. I think I won't know the truth until this car needs a windshield.

 

British Electrical theory posits that electrical systems operate via transporting smoke from the storage device (battery) to users of smoke... in the case of this thread... Circuitry in the windshield. The alternator manufactures smoke in the required quantity to replenish the battery as well as run needed circuits. Bigger conduits (wire) are able to pass more smoke. Thus; when a user of smoke fails there is often much smoke followed by none. Always loved electricals by the Prince of Darkness... Lucas.

 

That's outstanding.