Mercedes C400 Passenger Mirror
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Newbie
Joined: Mar 2026
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2015 c400
Mercedes C400 Passenger Mirror
Hello,
I have a 2015 C400, On the dash I receive an Error that says "Blind Spot Assist Inoperative".
All Sensors on the car work, when I reverse, the rear sensors work and when I park, the front sensors work. When i start the car, the blind spot detection light in the mirror does not light up and also in the winter, the heated mirror doesn't work. Which leads me to think that the issue is in the Mirror glass. I had the car scanned and I receive a the following error code B280815 Which indicates: "The output for the warning lamp 'Blind Spot Assist' has a
malfunction. There is a short circuit to positive or an open
circuit."
Before I go taking the mirror apart and maybe the door, has anyone ever had this problem? I it just the mirror glass that I need to replace or is it a wiring issue?
Any advice / help would greatly be appreciated, Also, my door handle lights have burn our on the passenger side, do i really need to take the door panel off to replace those?
I have a 2015 C400, On the dash I receive an Error that says "Blind Spot Assist Inoperative".
All Sensors on the car work, when I reverse, the rear sensors work and when I park, the front sensors work. When i start the car, the blind spot detection light in the mirror does not light up and also in the winter, the heated mirror doesn't work. Which leads me to think that the issue is in the Mirror glass. I had the car scanned and I receive a the following error code B280815 Which indicates: "The output for the warning lamp 'Blind Spot Assist' has a
malfunction. There is a short circuit to positive or an open
circuit."
Before I go taking the mirror apart and maybe the door, has anyone ever had this problem? I it just the mirror glass that I need to replace or is it a wiring issue?
Any advice / help would greatly be appreciated, Also, my door handle lights have burn our on the passenger side, do i really need to take the door panel off to replace those?
Last edited by tfitz; Mar 29, 2026 at 08:09 PM. Reason: typo
Out Of Control!!
Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
solderless DCU circuits
Hello,
I have a 2015 C400, On the dash I receive an Error that says "Blind Spot Assist Inoperative".
All Sensors on the car work, when I reverse, the rear sensors work and when I park, the front sensors work. When i start the car, the blind spot detection light in the mirror does not light up and also in the winter, the heated mirror doesn't work. Which leads me to think that the issue is in the Mirror glass. I had the car scanned and I receive a the following error code B280815 Which indicates: "The output for the warning lamp 'Blind Spot Assist' has a
malfunction. There is a short circuit to positive or an open
circuit."
Before I go taking the mirror apart and maybe the door, has anyone ever had this problem? I it just the mirror glass that I need to replace or is it a wiring issue?
Any advice / help would greatly be appreciated, Also, my door handle lights have burn our on the passenger side, do i really need to take the door panel off to replace those?
I have a 2015 C400, On the dash I receive an Error that says "Blind Spot Assist Inoperative".
All Sensors on the car work, when I reverse, the rear sensors work and when I park, the front sensors work. When i start the car, the blind spot detection light in the mirror does not light up and also in the winter, the heated mirror doesn't work. Which leads me to think that the issue is in the Mirror glass. I had the car scanned and I receive a the following error code B280815 Which indicates: "The output for the warning lamp 'Blind Spot Assist' has a
malfunction. There is a short circuit to positive or an open
circuit."
Before I go taking the mirror apart and maybe the door, has anyone ever had this problem? I it just the mirror glass that I need to replace or is it a wiring issue?
Any advice / help would greatly be appreciated, Also, my door handle lights have burn our on the passenger side, do i really need to take the door panel off to replace those?
These items are all controlled by the local Door Module. It very likely suffers from oxidized internal connections that were never factory soldered.
Once you're done with front passenger, the driver side will need same attention then the rear.
Last edited by CaliBenzDriver; Mar 30, 2026 at 01:01 PM.
Thread Starter
Newbie
Joined: Mar 2026
Posts: 2
Likes: 1
2015 c400
Mirror resolution
Hello,
I have a 2015 C400, On the dash I receive an Error that says "Blind Spot Assist Inoperative".
All Sensors on the car work, when I reverse, the rear sensors work and when I park, the front sensors work. When i start the car, the blind spot detection light in the mirror does not light up and also in the winter, the heated mirror doesn't work. Which leads me to think that the issue is in the Mirror glass. I had the car scanned and I receive a the following error code B280815 Which indicates: "The output for the warning lamp 'Blind Spot Assist' has a
malfunction. There is a short circuit to positive or an open
circuit."
Before I go taking the mirror apart and maybe the door, has anyone ever had this problem? I it just the mirror glass that I need to replace or is it a wiring issue?
Any advice / help would greatly be appreciated, Also, my door handle lights have burn our on the passenger side, do i really need to take the door panel off to replace those?
I have a 2015 C400, On the dash I receive an Error that says "Blind Spot Assist Inoperative".
All Sensors on the car work, when I reverse, the rear sensors work and when I park, the front sensors work. When i start the car, the blind spot detection light in the mirror does not light up and also in the winter, the heated mirror doesn't work. Which leads me to think that the issue is in the Mirror glass. I had the car scanned and I receive a the following error code B280815 Which indicates: "The output for the warning lamp 'Blind Spot Assist' has a
malfunction. There is a short circuit to positive or an open
circuit."
Before I go taking the mirror apart and maybe the door, has anyone ever had this problem? I it just the mirror glass that I need to replace or is it a wiring issue?
Any advice / help would greatly be appreciated, Also, my door handle lights have burn our on the passenger side, do i really need to take the door panel off to replace those?
MBWorld Fanatic!
Joined: Nov 2003
Posts: 2,415
Likes: 498
From: Earth
2015 C300 4Matic Sport
Aliexpress has quality mirrors for sale. I just got a mirror set with blind spot, heated, dimming for only $200.
MB wants $500 just for the dimming driver side mirror.
MBWorld Fanatic!
Joined: Nov 2003
Posts: 2,415
Likes: 498
From: Earth
2015 C300 4Matic Sport
You have noticec a few items around one of your front door have issues.
These items are all controlled by the local Door Module. It very likely suffers from oxidized internal connections that were never factory soldered.
Once you're done with front passenger, the driver side will need same attention then the rear.
These items are all controlled by the local Door Module. It very likely suffers from oxidized internal connections that were never factory soldered.
Once you're done with front passenger, the driver side will need same attention then the rear.
Every winter my heated seat button will stop working. In the past, I could bang on the door and it would instantly work again.
This winter it started staying ON completely and cooking my ***. I would have to shut car OFF to fix it.
I think I have a loose connector at the control module (hopefully) or maybe what you said.
MBWorld Fanatic!
Joined: Nov 2003
Posts: 2,415
Likes: 498
From: Earth
2015 C300 4Matic Sport
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