Harambe8

W164 2008 ml550

The command unit turns on and stuck on Mercedes logo and plays sound but I can't press any buttons or eject any cds

I've removed the fuse and replaced which I regret because now I don't have a radio station anymore and just static.

I saw a post on another site with someone with similar issue but different model vehicle, it does appear the command head unit could be very identical. He said he disconnected the nav module and it fixed it.

I've removed the command head unit but I cannot find or locate this navigation module he speaks of?

Harambe8

So I concluded the nav module is the physical nav DVD drive.

Takes 2 screws per side and slides out.

Unit now turns on.

So now I have to see if nav drive is faulty or command unit is. I'll have to test a known good DVD nav drive to determine the fault.

texterted

Thanks for posting your findings, good luck with it and let us know how you get on.

flybd5

I have a Comand head from my '09 550 that I replaced with a European head (totally incompatible, requires hard wiring for radio to work, etc.) The US unit worked fine when pulled, has '13 nav database and 6-disk changer. $300 + shipping from Germany (a lot cheaper than shipping in the other direction!)

Let me know if you are interested.