Just swapped COMANDs with a local seller here, demo'd it in his car and it was working properly, though I don't remember particularly looking for/at the lights on the buttons - I don't think he had his lights on though so that could be why I missed it.

All functions of the COMAND appear to work as advertised. BT connectivity works. DVD playback works. NAV works.

Any ideas why there would be no lights on the buttons?? I am going to pull it out tomorrow morning to see if we may have potentially left anything disconnected (or loose), and I suppose I'm going to check the fuse panel to see if anything was blown, but other than that I'm out of ideas. Thanks for the help!

 

Ok, went to the garage and checked it and everything was pulled out and reseated and is hooked up properly. Looks like I have a bad COMAND??

 

Anyone??

 

I don't see a separate fuse for lights for controls and buttons in my fuse diagram. You might try pulling and resetting all of the fuses related to your audio system (alternatively, disconnect the battery for 5 minutes or so, then reconnect; see https://mbworld.org/forums/s-class-w...dy-resets.html if you disconnect the battery).

I have never seen this problem reported, and don't honestly know where the control lights in the COMAND draw their power; however, they do respond to the lighting control on the instrument cluster, so without doubt it is connected to that control somehow.

Did you check the back of the COMAND unit for a fuse?

 

I've tried re-seating all of the fuses that I thought would relate to that area of the car; ones labeled Navigation, Radio, and so on. I did not try disconnecting the battery though, I suppose that could be worth a shot.

When I had the COMAND out I don't remember seeing any fuses back there to be honest, but I don't remember specifically looking for a fuse either to be honest.

I emailed a repair shop in London and this is what the gent had to say:

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ME:
Hello. I live in San Diego, California (US) and I have a Becker BE7023 in my 2004 W211 E55 (US Spec). It was purchased from eBay and I believe that I'm short on options regarding getting it fixed. The navigation works properly, as does the telephone connectivity. The DVD/CD/CDC functions all work as well.

The problem that I have is that all of the lights on the face of the COMAND - as in, the lights for the buttons - do NOT work. At all. Is this something that is repairable?? Thank you!

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HIM:
Hi Robert,


I think the problem is not with the unit. This unit communicate with the car on CAN bus. When you switch on the light then the board computer give order on CAN bus to the head unit switch the light on. Unfortunately it could happen when the head unit newer then car and not fitted for car. I can modify your unit, but in this case the light will always on.
I'm looking forward to hearing from you.

Kind Regards

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ME:
Thank you very much for your reply! If the fault does not lie within the unit, is it possible to address the "fault" within the CAN bus? Is there a way to flash an update or, is there maybe a potential upgrade?

I know you do this for a living and i don't want to take business out of your hands. I don't have a lot of funds and I also know that shipping to the UK would not only be time consuming but quite expensive as well. I very much appreciate any and all assistance you can lend however! If I understand your fix correctly, sounds like you would just hardwire the front panel to a 12V source so the lights are switched on when the car is switched on; much like an audio amplifier, correct??

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HIM:
This type of problem you can't fix with software update.
Yes you thought right it has to make a switch for the light. If you have experience with electronics, you will be able to modify the panel.

 

Ok so I tried disconnecting both batteries and let the car sit for an hour and then reconnected both batteries. Upon reconnecting, I had to sync the windows, the moon roof, and the headlight cornering.... But my seat memory remained, as did all of my radio presets.

What does it take to reset everything to a point where the car things it's starting over from scratch??

 

Pretty much what you have already done - disconnecting and reconnecting the battery.

I don't know if a setting via DAS would cure the problem. You would have to check with a dealer or a good independent familiar with the MB diagnostic computer system. The gent with whom you corresponded didn't seem to hold out much hope of that.

 

Thanks for the response. Aside from the initial problem... I'm sort of stumped as to why the radio presets and seat memory were not erased from the car upon leaving both batteries disconnected for over an hour. Stumped and sort of annoyed lol.

There must be another module somewhere in the car with a battery (CMOS maybe?) that is retaining these settings. Body control module maybe?