It appears my antenna is history. It is getting current from radio (aftermarket Pioneer AM-FM-CD installed by previous owner) but I can't hear motor working. I assume this means motor is gone since it is getting power, and I can't just replace the mast???
Any other suggestions for verification motor is fried??? And if so, best place to obtain compete antenna w/motor, as I don't know you can just replace motor. I'm just a so-so do-it-yourselfer, so help is welcome. Radio works OK, but several stations fuzzy. CD, of course, works fine.
CAN I JUST FORCE UP THIS ANTENNA A BIT UNTIL I REPLACE to improve reception??? If motor gone, would that hurt anything???

85 300SD,
225k Astral Silver

I would consider this:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7930218729&rd=1&sspagename=STRK%3AMEWA%3AIT

A simple cheap alternative.
Compared to OEM
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1D6124YYN1D6125BVW&year=1985&make=MB&model=300-SD-002&category=Z&part=Power+Antenna

See Note!
Does not include cables, antenna seal, or associated hardware. For replacement mast use 126 827 00 01.
For models prior to 1984, requires extensive modification to retrofit. Requires (1) 123 540 94 08 antenna cable (1) 002 820 99 10 antenna switch (1) 126 820 81 14 bracket (1) 126 827 15 98 antenna seal and (1) 123 990 11 91 retainer.

Z4002-90204 Power Antenna Hirschmann IN STOCK $195.11

__________________
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https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
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Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

Your internal relay cam has probably broken just as mine did on the 240D.

This place supplies parts but you will have to replace a couple of them, they do not make the cam assembly any more. They are a little slow to reply.

http://www.geocities.com/odemer@sbcglobal.net/

I did install the Hirschman Auto 2040 in the 240D. Had to wire in the Mercedes wire harness so the plug at the end of the wire harness will connect. The middle antenna switch position will NOT work, never used it anyway.

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

What is the purpose of the middle position anyway? Just half antenna?

I think the middle position leaves the antenna wherever it's at, car running or not.