Good news! After fiddling with it and then talking to 2Phast he suggested disconnecting the battery, which got me thinking... although the instructions in the changer say to 'disconnect the changer from the car when changing the M-bus/Ai-net switch', the keys were still in the ignition, and that may have affected the *memory* of the head unit. Sure enough, after pulling the changer and setting the switch, *then* turning on the car.... voila! Seems to be working fine now, although I need to burn a few more MP3 cd's to test out since the ones I'm using right now were burned with a well-worn laser, and haven't shown 100% compatibility with newer MP3 devices.

thanks for the help!

-Dr. J

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1995 Mercedes E420

Bilstein Sport Shocks
Eibach Sport Springs
ATE Slotted Front Rotors
Stainless Steel Brake Lines
Motul Race Fluid
Euro Headlights w/PIAA superwhites
17" Monoblock Rims
K&N Air Filters
Matched Leather/Burlwood Shift Knob
S Class Leather/Burlwood Steering Wheel