I am pulling my hair out
every one has told me the BT Puck with tail is plug and play on my
2004 E320 4matic wagon - not so fast
the blue tooth puck when plugged in does not light the blue light on it
so I look thru the vast info on the web a decided to dig in
when I removed the com cover in the cargo area I saw two open areas
compinsator?
http://4.bp.blogspot.com/_ziYiJvJGQy...h/DSCF4593.JPG
Clueless to what goes in this space, but as you can see I am reading the directions
http://2.bp.blogspot.com/_ziYiJvJGQy...h/DSCF4594.JPG
while we are at it what goes above the GPS Drive
http://2.bp.blogspot.com/_ziYiJvJGQy...h/DSCF4596.JPG
or below it
http://1.bp.blogspot.com/_ziYiJvJGQy...h/DSCF4597.JPG
relay "D" and fuses 17-18-19-20 are missing
http://4.bp.blogspot.com/_ziYiJvJGQy...h/DSCF4595.JPG
HELPPPPPPPPP!!!!!!
BTW I added the GPS and SAT Radio my self - can't say enough good things about the MBDoctor

 

The puck with tail was plug and play on my car which is also a 2004 E320 4matic (wagon). Maybe you have a wiring problem or a defective puck.

My car was Jan 2004 build.