So The Frost is Here Where is the rear Window Defrost
Thread Starter
Junior Member
Joined: Sep 2019
Posts: 28
Likes: 3
From: Ohio
2017 S63, 2003 SL500, 2010 S550, 2008 GL 450
So The Frost is Here Where is the rear Window Defrost
Morning all, so new to me 2010 S550 has a defrost issue apparently. First frost of year, start car click on switch for rear defrost and light on switch is on but seems rear window defrost does not do anything reclicked switch after its first 10 minutes same result nothing... some sort of magic I'm missing? Any help would be great.
Member
Joined: Dec 2015
Posts: 192
Likes: 41
2007 S600
Not up my 2010 if they made a change, but yeah the defroster is laughable. One of the first things I noticed as in a "Really?" moment.
Microscopic filaments in the back glass that do basically nothing compared to the big ones on you dad's Chevy.
Microscopic filaments in the back glass that do basically nothing compared to the big ones on you dad's Chevy.
Member
Joined: Jul 2016
Posts: 108
Likes: 23
2018 S450 4Matic, 2020 GLE450 4Matic, 2010 S550 4Matic(sold), 2012 ML350 4Matic(sold)
Something is apparently wrong with yours. Mine works very effectively. Just a couple of minutes from frosty to clear.
Have you scanned for codes?
Have you scanned for codes?
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Thread Starter
Junior Member
Joined: Sep 2019
Posts: 28
Likes: 3
From: Ohio
2017 S63, 2003 SL500, 2010 S550, 2008 GL 450
So ignored the terrible defrost till just this week, relay good (swapped from other MB) so has power just unbelievable how poor this system is saw no temp increase on window with laser thermometer, have now chased wires that connect to glass but don't want to blow a couple hundred for some MB Service writer to explain it works fine
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Senior Member
Joined: Nov 2002
Posts: 303
Likes: 25
The rear defrost does work well on mine - however the service literature also points out that the illumination of the rear defrost light may be deceptive. Depending on ambient temperature, and main bust voltage, the system may not immediately activate the rear defrost even though the light is illuminated. What this magic formula is remains undocumented in the literature.
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Joined: Sep 2005
Posts: 6,189
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From: Albuquerque
'10 CL550, '12 GL550
The rear defrost does work well on mine - however the service literature also points out that the illumination of the rear defrost light may be deceptive. Depending on ambient temperature, and main bust voltage, the system may not immediately activate the rear defrost even though the light is illuminated. What this magic formula is remains undocumented in the literature.
Thread Starter
Junior Member
Joined: Sep 2019
Posts: 28
Likes: 3
From: Ohio
2017 S63, 2003 SL500, 2010 S550, 2008 GL 450
The rear defrost does work well on mine - however the service literature also points out that the illumination of the rear defrost light may be deceptive. Depending on ambient temperature, and main bust voltage, the system may not immediately activate the rear defrost even though the light is illuminated. What this magic formula is remains undocumented in the literature.
