Back when I fixed up my Daughters car for her. I installed a Hirschmann Auto 2040 antenna for her. The OEM antenna was $220 and the A2040 antenna is only $50 or so. If fits nicely and worked for almost a year. Just installed a new replacement unit today. The old unit would not fully retract. Tried cleaning the mast but that did not work. Since it was under warranty I had a new one shipped to me and reinstalled it.
The antenna will only work in either the fully retracted or the fully extended position. The A2040 model does not have the intermittent extended position. The antenna switch in the car will work but not in the middle position. but will work in the other postiions as per the OEM manual
The antenna will extend when the radiao is turned on and fully retract when the radio or car is turned off.
To wire the antenna I soldered the old cable onto the new wires and used heat shrink on the setup. Wire the antenna the following way. Cut the wire harness from the old antenna, giving yourself as much cable as possible.
Wire the Mercedes wires to the A2040 unit as below

Mercedes cable------------- A2040 wires

Brown ----------------------Black
Blue------------------------Red
Yellow/Green---------------White.

Cut the other wires since they will not be used. Use heat shrink to seal the wires and solder joints.
Mount the Antenna just as the old unit was and your set.
Choose the grommet that will best mount the antenna for your car.

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

good show. thanks.

george