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Good morning!

The heated door mirror on the driver's side of my 2014 S205 seems to be malfunctioning. I mention this because on the two or three occasions I have attempted to remove condensation from the mirrors in the morning, the passenger mirror clears after a few minutes, however the driver's side remains obscured. The back window defogs adequately. Can we reasonably conclude that the issue originates from the mirror glass, or is there an astute method to identify the problem without disassembling components and testing for voltage at the wire connection, or only replacing the mirror glass and relying on chance? The mirror glass has automatic dimming functionality, which works well.


I am 99% certain that the component number for the mirror glass is A0998100216. Based on my online research, these items are prohibitively pricey while new and not very affordable when used. Is it possible for a dealer to be less expensive, assuming they remain accessible?

I have located one video demonstrating the removal of the mirror cover prior to dislodging the glass from the mounting bracket from behind, and another video illustrating the technique of pulling the glass off the bracket from the front using fingers. Does anybody has expertise with this?

Thank you.

This morning, I verified via a tactile examination that the passenger door mirror is warming, however the driver's door mirror is not. Further investigation indicates that this issue may stem from several factors, including wiring malfunctions; thus, I will refrain from hastily purchasing a new mirror glass until I have assessed the heating element and the wiring connected to the mirror.

Some individuals have remarked that the heated mirrors activate automatically when the external temperature reaches a certain threshold. Is this applicable to my vehicle, or indeed to all Mercedes-Benz models of my generation?


Thank you.

The 2014 vehicles may vary, however the cables servicing the several duties of the wing mirrors are exceedingly thin to facilitate flexibility. Consequently, the majority of owners who have experienced difficulties refrain from folding the mirrors unless it is imperative.


By removing the mirror, you may detach the two wires connected to the heater to ascertain if the heating coil in the glass exhibits an open circuit, while simultaneously measuring the voltage across the two supply wires.

That is the straightforward aspect.

Disassembling the whole assembly necessitates the removal of the inner door panel to access the SAM unit that serves the mirror in order to unhook the plug for wire continuity testing.

It is likely comparable to a 2014 model, given its similarity to the 2006 C class.

Indeed, 15 degrees Celsius.

I am optimistic that the failure lies with the element or another component inside the mirror housing, since, despite the cost, replacing the mirror glass is rather straightforward.

15 degrees Celsius is quite elevated; yet, I like the concept fundamentally. This morning, the temperature was 8-9 degrees Celsius, and my driver's mirror fogged up twice throughout my commute to work. That occurred after I had previously cleared it with my hand and deactivated the back screen demister. The passenger side did not fog up again, possibly due to leftover heat or ongoing heating.

For those curious, with the mirror glass fully adjusted inwards, it may be removed using just your fingers behind the outside edge. However, mine needed some energy to do this (much more than anticipated), perhaps due to the glass having never been removed before. The second attempt I made (merely for amusement) proved much simpler. Ultimately, I successfully refrained from causing any damage, to the best of my knowledge.

I have confirmed 12V at the wires with the rear demister activated. The unfavorable news is that I likely need a new mirror glass. I measured the resistance of the heating element to be around 85 ohms, which I estimate would provide less than 2 watts of heating power, certainly insufficient. The consensus among individuals is that 10 ohms is about optimal, yielding around 15 watts of heating power. I refrained from risking more complications by removing the passenger mirror glass for testing, therefore I trust that my assessment is accurate.