i was in your shoes earlier when i was installing a p6000 pioneer in my 85 190e.
You are going to need to bypass the fader switch which was a pain.
Memory (+12v Constant) Red
Ignition (+12v Switched) Black/Yellow
Ground (-) Brown
Dimmer (none) (Though i read that you can tap into the light with the ashtray/cigarette lighter)
Power Antenna Blue
oh yea, technically i think that this post is supposed to be in the audio forum.
Search the audio forum for speaker wire colors and directions on how to bypass the fader.
For more specific 190e info there is a great forum @ Delphi which was created by Clinton. He post on here sometimes.
A href="http://www.delphi.com/MBNZ190E/start">190e forum</a>
[Edited by dug on 01-01-2001 at 11:25 PM]