Mercedes-Benz Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter #1
Have a 2005 ML500. If the key is in the acc position the windows (all 4) and outside mirrors work fine. When you start the engine the windows and mirrors work for about a minute and then they are dead. turn off the engine and turn the key to acc and everything works fine again. Voltage is 14V at fuse 25 the entire time the engine is running, power is constant. Trying to figure out why my windows wont work if I have power continuously at the window fuses and how it is related to whether the engine is running or not. I disconnected the battery for 5- 10 minutes to do a computer reset and also cleaned ground connections. Maybe a master window switch is going bad ? Need to figure out what to check next.

Thanks
 

·
Registered
Joined
·
269 Posts
Have a 2005 ML500. If the key is in the acc position the windows (all 4) and outside mirrors work fine. When you start the engine the windows and mirrors work for about a minute and then they are dead. turn off the engine and turn the key to acc and everything works fine again. Voltage is 14V at fuse 25 the entire time the engine is running, power is constant. Trying to figure out why my windows wont work if I have power continuously at the window fuses and how it is related to whether the engine is running or not. I disconnected the battery for 5- 10 minutes to do a computer reset and also cleaned ground connections. Maybe a master window switch is going bad ? Need to figure out what to check next.

Thanks
The only thing that comes to mine is: ACC is at 12 something volts and with engine running it's above 14 volts on start up.. Some kind of a problem with the SAM not being able to handle the 14v..????????
 

·
Premium Member
Joined
·
4,449 Posts
When you go from ACC to IGN without starting the engine do they work?
Sounds like an AAM issue.

Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
12 Posts
Discussion Starter #4
When going from ACC to start the windows and mirrors work but just for about a minute, then they go dead.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #6
Windows and mirror work fine when the key is on n the acc position, they don’t time out like they do when the engine is running


Sent from my iPhone using Tapatalk
 

·
Premium Member
Joined
·
4,449 Posts
Sounds to me like the AAM thinks the car has been turned off. In the window section anyway. It could be the ignition switch is loosing power at some stage in turning it and the AAM is going into off time out mode.
In the 2000 model after off, you get power to the widows for a minute or so or until the door is opened.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
12 Posts
Discussion Starter #9
Is the lower control panel the same thing as the master switch module in the console? I checked the link you attached and it looks like it is


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
6,615 Posts
Is the lower control panel the same thing as the master switch module in the console? I checked the link you attached and it looks like it is


Sent from my iPhone using Tapatalk
Yes, it is. Is is not really a switch but a keyboard.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #11
I checked the lower control panel an no corrosion. I then measured the voltage at the window fuses and has 15.6 volts. I suspected I had a bad voltage regulator and when the voltage became too high the lower control panel shut down to prevent damage. Replaced the alternator with constant output of 13.9 volts and the window problem was solved


Sent from my iPhone using Tapatalk
 
1 - 13 of 13 Posts
About this Discussion
12 Replies
4 Participants
bobby735
Mercedes-Benz Forum
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!
Full Forum Listing
Top