Rear Window Heater
Thread Starter
Member
Joined: Nov 2017
Posts: 127
Likes: 27
From: Lincoln, CA
2018 S450
Rear Window Heater
I can't find any information online for this so I thought I would ask the forum if anyone knows how this works. Several days ago I tried the rear window heater for the first time. It was a foggy misty day and the window had a coating of light moisture. It was a short trip home so I only had it on for maybe 6 or 7 minutes. I noticed no effect at all. On previous cars I would see "bands" of clearing where the heater wires were imbedded in the glass. I looked at the window more closely after I got home and noticed imbedded wires only in the top 6 inches of the rear window and they kind of looked like antenna wires. How is this supposed to work? I have a 2018 S450.
Super Member
Joined: Oct 2010
Posts: 764
Likes: 10
From: North Carolina
2010 E350, 2015 S550
I think that it takes a bit longer than other defroster/heaters. The element is actually very fine cross wires that cover the complete rear window. The wires that you can easily see are not the heater wires. I used mine for the first time a few weeks ago. Not much use hear in the the south but it worked well. It just took a bit longer than what you may be used to.
Senior Member
Joined: Jan 2013
Posts: 304
Likes: 75
2022 AMG GT 53, 2020 Sl450. Did drive 2018 S450
I can't find any information online for this so I thought I would ask the forum if anyone knows how this works. Several days ago I tried the rear window heater for the first time. It was a foggy misty day and the window had a coating of light moisture. It was a short trip home so I only had it on for maybe 6 or 7 minutes. I noticed no effect at all. On previous cars I would see "bands" of clearing where the heater wires were imbedded in the glass. I looked at the window more closely after I got home and noticed imbedded wires only in the top 6 inches of the rear window and they kind of looked like antenna wires. How is this supposed to work? I have a 2018 S450.
Member
Joined: Dec 2017
Posts: 184
Likes: 24
From: Portland, OR
2018 S560; 2021 GLS450
Are the heating wires on the rear window literally embedded into the glass, or are they over the inner surface of the window like in other cars? It does not look like one can feel them, so it feels like they are in the glass itself, unlike the antenna wires. Also an ohmmeter read agrees with that, for both the heater and the antenna wires (where there is no closed circuit on the heater wires, and it is all closed on the antenna wires).
I had to check this as there was a slick-on temp plate holder that was affixed to the inner portion of the window, and I wanted to make sure that these wires did not get damaged with it. If they are inside the window, then they will not get damaged obviously...
However, while I did not try it more than once (without condensation, just o see the effects on the droplets outside), I agree that these things do not work like other cars (my F10 was very strong in this department). Or I managed to break them somehow.
I had to check this as there was a slick-on temp plate holder that was affixed to the inner portion of the window, and I wanted to make sure that these wires did not get damaged with it. If they are inside the window, then they will not get damaged obviously...
However, while I did not try it more than once (without condensation, just o see the effects on the droplets outside), I agree that these things do not work like other cars (my F10 was very strong in this department). Or I managed to break them somehow.
Member
Joined: Dec 2017
Posts: 184
Likes: 24
From: Portland, OR
2018 S560; 2021 GLS450
Well, had the chance to try it for real this weekend (darn Northwest weather). Good news is I did not damage it, looks like all wires embedded into the glass work fine and warm up fine. Bad news is, it shows effect shortly after I turn it on the second time, after the first round auto-shuts off after the timer expires... It is what it is I guess...
