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Does the car really have 3 FMs? Antenna Diversity Module?

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
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billy_beemer
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Does the car really have 3 FMs? Antenna Diversity Module?

Post by billy_beemer » Wed Mar 25, 2015 1:31 pm

Well clearly I'm asking as the FM reception on my car is virtually non-existant. Autotune finds nothing, Manual tune just about finds a station but you can't listen to - it just sounds like the aerial is loose, reminds me of the old days of waving a piece of wire around your bedroom finding somewhere decent to blu-tac it.

"FM Antenna '2'" (item 6) aka the external aerial is connected in some form as if you disconnect it you loose all reception. So if there are in fact 3 FM aerials this would suggest the other 2 aren't connected and that maybe there's a problem with the Diversity module?

If a vehicle is ordered with a CIC, the iboc tuner is located inside the CIC. If the vehicle is
equipped with a RAD2, the IBOC control unit is mounted in a separate location.
Antenna Locations
The antenna system on the E89 consists of 3 FM, 1 AM, 1 GPS, 2 Telephone and an
SDARS antenna. Their locations are illustrated below:
Overview of Antennas

Image
windows 7 screenshot

If anyone has any ideas on what to check I'm more than happy to pull things apart and photograph / document the fix.......... however right now, not sure whether to start near the rear of the vehicle or the head unit?

EDIT as google suggests this is the Antenna Diversity Module:
viewtopic.php?f=31&t=11936&p=181957&hil ... le#p181957

On the E85 this looks quite easy to get at, anyone know if its the same on the E89? worth a look!
Last edited by billy_beemer on Fri Mar 27, 2015 2:16 pm, edited 1 time in total.
Z4M gone / 2009 35i just arrived / E Class Merc going strong

matsmith749
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Re: Does the car really have 3 FM Aerials?

Post by matsmith749 » Wed Mar 25, 2015 3:00 pm

First thing I would do is to swap out the external antenna for a replacement.

It's quick & easy to do, doesn't cost much & may save you a lot of time.

Matt
From Jan 2023 2016 e89 Z4 35is / mineral white / coral red interior / all the extras
SOLD 2010 e89 Z4 35is / space grey / coral red interior / all the extras
SOLD 2007 e85 Z4 3.0 si sport / midnight blue / champagne interior

billy_beemer
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Posts: 134
Joined: Thu Sep 29, 2011 4:18 pm

Re: Does the car really have 3 FM Aerials?

Post by billy_beemer » Wed Mar 25, 2015 5:04 pm

matsmith749 wrote:First thing I would do is to swap out the external antenna for a replacement.

It's quick & easy to do, doesn't cost much & may save you a lot of time.

Matt
Did that with one from a 3 series......... was exactly the same :(
Z4M gone / 2009 35i just arrived / E Class Merc going strong

billy_beemer
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Posts: 134
Joined: Thu Sep 29, 2011 4:18 pm

Re: Does the car really have 3 FMs? Antenna Diversity Module

Post by billy_beemer » Fri Mar 27, 2015 2:17 pm

google suggests this is the Antenna Diversity Module:

viewtopic.php?f=31&t=11936&p=181957&hilit=antenna+diversity+module#p181957

On the E85 this looks quite easy to get at, anyone know if its the same on the E89? worth a look!
Z4M gone / 2009 35i just arrived / E Class Merc going strong

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