Anyone used the Windshield Heater?

Supposedly the Range Extender package includes an electric windshield heater, but I see no reference to it in the owners manual. The dealer did explain how the RangeExtender is activated (use before to charge over 85% or after to use bottom 10% of battery which is normally locked out). But he forgot to explain how the windshield heater works, so I am left using the climate control defroster which is a battery killer.

Has anybody tried their electric windshield heater?

Sorry I don't have one.

I would imagine you just use the Max Defrost Button on the climate control and instead of it it being air, it will use the electric heater instead.

JupiterRed said:

Sorry I don't have one.

I would imagine you just use the Max Defrost Button on the climate control and instead of it it being air, it will use the electric heater instead.

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That's sort of what I thought. However, unlike RANGE PLUS, there is no indication in the manual that the electric windshield heater even exists which I find a little troubling...

I also have not found out how to use the electrically heated windshield. The max front defrost button seems to only activate the AC (to dry the air) and a heated blower on the front windshield, which defrosts or de-fogs from the bottom up, unlike an electrical heater that initially cleans up the areas around the grid of heating elements.

Checking the manual there are two cases when it references the windshield heating. One on page 118 is when you turn on the max defrost button. The second reference is when you use preconditioning prior to driving.

In both of these cases besides blowing hot air turning on normal defrost operations, it mentions turning on windshield heating.

I also saw what was in the manual. I was hoping that maybe there was a way to just use the element within the windshield.

HarleyMYK said:

I also saw what was in the manual. I was hoping that maybe there was a way to just use the element within the windshield.

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Yup that is what expected before I picked up the car. I asked my MB Salesman after I started this topic, and he was kind enough to send me a PDF explaining the Heated Windshield system (including electrical design and operation). Here is a paste of the operations section:


Although I do not see a 'heated windshield button', it unfortunately appears that, as everyone had guessed, the Max Defrost button operates BOTH the electric windshield heater AND the fan. Certainly would've been nice if they added a sentence like "the Range Extender package includes a windshield heater as well as the fan". Lost in translation I guess.

I'll admit that the window clears fast, even after the car has been out in the cold for a while, but the fan seems like a waste of energy and I too would like to be able to have the option to just use the heater like rear window defogger.

I wonder what would happen if you started with the max defrost and then turned the fan down manually would that keep the heated windshield operations still functional.

It seems like the answer is no Max Defrost the front window and then manually turn the blower down to minimum. You can actually feel the heat coming off the glass and it warms your face and the entire top of the driver's compartment. This seems to use less energy than the "heating" system. So combination of windshield heater and seat heater is good, I just wish for a heated steering wheel and something in the footwell. In fact the seat heater is too strong even on the lowest setting for a 45 minute drive, I always have to turn it off and on throughout the trip.
3 degrees Fahrenheit here in NYC today.

Does the AC button come on with Max Defrost. Would you turn that off too, to save a bit of power?

wtzouris said:

It seems like the answer is no Max Defrost the front window and then manually turn the blower down to minimum. You can actually feel the heat coming off the glass and it warms your face and the entire top of the driver's compartment.

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Interesting. I've been using just that and the window fogs up in a few seconds, I need Max defrost on to get the window clear. More importantly I do not feel any heat from the windshield with the climate control of defrost mode just the blower. Maybe my fuse blown or its off b/c I do feet and defrost mode?

So were the steps to get your face warm:
1. Turn on Max Defrost
2. turn down fan
3. Wait a few minutes and feel the heat?

Do you happen to have the range package? I believe this window heating is specific to that package.

rdavis0521 said:

Do you happen to have the range package? I believe this window heating is specific to that package.

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Yup I have the range package.

I did some testing tonight. My face gets warm with the fan on low after a minute or two, but that is because there is hot air coming out from the dash just like ay other windshield defroster, not because the windshield is being heated electrically. So I don't see how this is any more efficient than any other windshield defroster in any other car, other than maybe there is a possibly an air heating element closer to the window. I was wondering how anything could directly heat the windshield without any visible heating elements, now I know that's not what they meant by windshield heater.

Direct heaters like seat heaters, rear window defoggers, and steering wheel heaters are an order of magnitude more efficient than blowing air over heating elements. This is a truly disappointing discovery.

padamson1 said:

rdavis0521 said:

Do you happen to have the range package? I believe this window heating is specific to that package.

Click to expand...

Yup I have the range package.

I did some testing tonight. My face gets warm with the fan on low after a minute or two, but that is because there is hot air coming out from the dash just like ay other windshield defroster, not because the windshield is being heated electrically. So I don't see how this is any more efficient than any other windshield defroster in any other car, other than maybe there is a possibly an air heating element closer to the window. I was wondering how anything could directly heat the windshield without any visible heating elements, now I know that's not what they meant by windshield heater.

Direct heaters like seat heaters, rear window defoggers, and steering wheel heaters are an order of magnitude more efficient than blowing air over heating elements. This is a truly disappointing discovery.

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I also have the range package and can't figure this out. I did notice, if you look at the windshield from the outside, from a certain angle, there seems to be some kind of purplish tint. Could this be specific to the electronic heated windshield?

Mine is the same. I have the range package, and my front window has a pinkish/purplish cast to it. There's some kind of coating there for sure. Not sure if it's electric or not. Haven't really tried this, as it's generally warm in SoCal.

What doesn't make sense to me is if you turn on the Max Defrost, does not the regular heater system come on as well? Certainly you can turn down the fan, but that isn't turning off the regular system. There's got to be something to this. The sales configuration guide definitely said heated windshield with the range option.

I also have the range package and I press Max Defrost (Front Window) and then turn the fan all the way down to 1 bar. After a few minutes, I feel the heat coming off the window on my face -- the whole upper part of the cabin really. It's way more heat than the fan on 1 bar could produce with the heater. So I think it definitely works and supposedly it is very efficient. Together with the seat heaters, the only issue is that the footwell gets very cold. Too bad they couldn't find a way to electrically heat down there -- that way I could keep all ventilation A/C off.
12 degrees here in NYC...

Not sure if an electric car is any different but in normal gas cars the AC compressor won't actually come on if the outside temperature is below a certain point something like 50 or 45 comes to mind. The AC light in the car might be lit but it won't actually engage.

wtzouris said:

I also have the range package and I press Max Defrost (Front Window) and then turn the fan all the way down to 1 bar. After a few minutes, I feel the heat coming off the window on my face -- the whole upper part of the cabin really. It's way more heat than the fan on 1 bar could produce with the heater. So I think it definitely works and supposedly it is very efficient. Together with the seat heaters, the only issue is that the footwell gets very cold. Too bad they couldn't find a way to electrically heat down there -- that way I could keep all ventilation A/C off.
12 degrees here in NYC...

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Does the windshield actually feel warm? My windshield was only warm down near the dash (where the fan is), nowhere else. The warm parts of the windshield are only above the vent, fanning out upwards from there (just like any other windshield heated by a blower). If you feel down low about 5inches outside where the fan is on the center of the dash. It's cold as ice. I also felt up top by outside massive thing that holds the rearview mirror (to me the logical location for any heating element in the windshield), ice cold up there too. Of course it's warm underneath it, but extends dow to the fan (again). Oh if I only had an IR camera, if this debate continues, I'll see if I can borrow one.

If the windshield really had its own heat source, it should have an even temperature across it. It might be warmer above the dash vent, but certainly the rest (if it had its own heat source) would not be nearly as cold as outside the car. Maybe I'm not patient enough, but in my car there is no sign of any heat coming from anywhere other than the fan vent down on the dash.

If I have to take it in for a SW upgrade, I'm going to ask the tech dudes (Hanz & Franz) to show me the 'windshield heater' in action. So they can call me a 'girly man in my puny B-Class ED'. ;-)

This is crazy...I have the range package and I've been trying to figure out how to use the window heater too. There is a button I keep thinking is the function. It's the button that is in between the driver seat warmer and the E-S mode button. I push it and then it turns off right away. I haven't bothered going to the dealer yet cause they know nothing about the car. I've been using the climate control window defrosting function but I thought there was a special feature this trim model came with. Thanks for posting this topic.

Nevermind...that button I was talking about maintains the interior temperature up to 50 min when the car is stopped and the key is out.