abercanadian

Hi, this is a comand unit on a 2006 R350.

The radio works with station selection, volume, scan buttons all functioning properly as does the CD load/eject mechanism. CD also plays. Prior to disconnecting the ribbon cable to the screen, screen display was illegible comprised of a bunch of coloured lines.

Thinking the problem was the connection to the screen, I disconnected the ribbon cable at the screen end and sprayed some contact cleaner on the connector/cable. When I reconnected the screen there was no longer anything displayed, screen appeared to be dead, so I bought a good used screen.

After fitting the new screen, I had the same result, nothing displayed.

Any advice as to how to proceed? I believe the unit was powered up at some point without the screen in place.

TIA

Larry

Jrichards75

if you plugged it back in too quickly after cleaning it might have blown a fuse. I'm not sure if the screen has a fuse or not, but sounds like it could be as simple as that.

abercanadian

I did check the general unit fuse at the rear of the comand unit and it was fine, but of course there is a possibility that there's another small fuse inside the comand itself. I just bought a non-functional comand for parts from eBay that I intend to dismantle so maybe that will provide some answers.

Scanning the car, the comand section of the scan showed all components passing OK so I feel the main problem must be with the screen or possibly the ribbon cable connection.

Thanks for the reply BTW.

Larry

abercanadian

Found a break in the ribbon cable. Will report back after replacement.

Larry

abercanadian

Ribbon cable made no difference. Eventually bought a non-working but clean unit from eBay, disassembled the front panels and swapped the screen control boards and screens. Had to swap trim panel too, as non-working unit was from a later year M-class.
Fortunately screen controller boards were identical and after exchanging the parts the comand unit now functions as designed.

Larry

Tomfitz

I like when people come back and post about the actual solution. Thanks!

What did you scan the comand with? I'm looking for a scanner now too.

abercanadian

Hi. I bought an XTOOL A30M, couldn't recommend it any higher, it is a fantastic tool.