Aftermarket Radio Poor Reception - W203 CLC 2008

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Jadee

New Member
Joined
May 3, 2014
Messages
15
Location
West Country
Car
A & C Class Coupe
I have recently swapped out my Audio 20 radio for a Sony XAV-602BT with the TomTom Sat Nav module. All works well sound, sat nav, Bluetooth, steering controls etc. apart from radio reception which is almost non existent.

I used the Connects2 kit to fit and cable the Sony unit - which was very easy.

I understand that pin 13 (black wire) needs power for the amplified antenna - this is there (Connects2 does this and the Sony provides 12V on this pin).

The old Audio 20 had two Fakra connections - black and mustard - the black one gives no signal - the mustard a few FM stations.

I have ordered a twin Fakra connector - Connects2 CT27AA25 - Universal Twin Fakra to DIN Aerial Antenna Adaptor - which I gather from some posts others say has worked.

Has anyone any further advice that would help.

BTW I find the forums a wealth of knowledge.
 
I think the aerial may need to be powered? Have you connected the blue accessory lead from the head unit to the correct cable in the loom? (Not the barrel thing on the fakra converter kit, it'll just get really hot)
 
Yes that's the - Blue ISO wire - which has 12v from the Sony Head Unit when powered on - which is connected to pin 13 in the Mercedes Quad Block (black wire).

Which from what I can read appears to be the power input to the antenna. The old Audio 20 unit received a good reception hence why I am stuck.
 
The Audio 20 radio is part number A2038704589 - Model number MF2730 - February 2008 - if that's any help.

Cannot believe there is no one who can help - has no-one changed a head unit and had a problem with reception - or did you all give up and stick with the audio 20 or a very expensive Mercedes audio upgrade?
 
If your CLC is the same as the W203 I had, there is an aerial amplifier in the headlining over the rear window. Maybe something has caused a problem with that.

Your best bet may be to phone comandonline, who seem to know just about everything about MB electronic ICE type stuff!
 
The Black fakra is the one to use.

Your car being a 2008 may be a model year 2009. In which case antenna amp power is probably on pin 6 of the white microphone lead. did the previous audio-20 have built in bluetooth with a beige like screen or was it one of the earlier ones with a sort of mauve coloured LCD type display and no bluetooth?
 
The Audio 20 did not have Bluetooth and its a `mauve' LCD display (when turned off its a reddy colour) - the Radio has February 2008 written on it.
 
I tried the dual adapter Connects2 CT27AA25 and it appears to have made no difference at all.

If I plug back in the Audio 20 reception is great - the Sony is better reception with just the fakra to din cable in - so the Merc aerial is doing very little :(

Fitting radios used to be so easy.... any ideas :)
 
See my reply to your email reference power and phantom feed.
 
Sorted eventually

It seems there is a lot of secrecy over the radio installations on Mercedes - not sure why - apart from everyone wanting to make a killing by charging for services rather than helping club members.

Eventually the problem with no reception was sorted by finding out the connections on the rear screen to antenna amplifier were loose fixing this cured the problem with no reception.

There are also a number of car radio installation companies in the west country and around who are unable to answer emails even if chased by phoning - business must be very good for them.

For info - Command.com emails to me where -

Okay, this sounds like either the antenna amp in the rear has failed or you do not have 12v going down the wire that was in pin 13 of the main
q
uadlock.

Also, plug the audio-20 in and meter the black fakra output to see if the standard unit is phantom feeding the aerial aswell. If it is then the DIN converter isnt sending the phantom feed and you will need a different converter. The AUX connector has nothing to do with this, nor the white connector, thats only for units that are the newer NTG 2.5 generation.


Halfords where more helpful than the forum and they did not charge me for the advice - make you wonder doesn't it....
 
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Are you slagging the guys at comand ?

Perhaps best to stick to halfords in future ;)
 
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Not slagging anyone - not my style - I'm just surprised by methods used.

As I said Mercedes audio just seems to be a very secretive subject on this forum - if you go to other forum's / countries for Mercedes the answers are a lot more helpful and placed in the posts rather than emails.

Read into what I have posted as you may.
 
Helluva coincidence, that. Your connections on the rear screen failing at the same time as you installed the radio.
 
I used to lose my radio signal occasionally - all I can think of is that the Sony unit is more sensitive that the original Mercedes OEM unit.
Not sure re your `Helluva coincidence' comment perhaps you'd like to explain?
 
It seems there is a lot of secrecy over the radio installations on Mercedes - not sure why - apart from everyone wanting to make a killing by charging for services rather than helping club members.

Eventually the problem with no reception was sorted by finding out the connections on the rear screen to antenna amplifier were loose fixing this cured the problem with no reception.

There are also a number of car radio installation companies in the west country and around who are unable to answer emails even if chased by phoning - business must be very good for them.

For info - Command.com emails to me where -

Okay, this sounds like either the antenna amp in the rear has failed or you do not have 12v going down the wire that was in pin 13 of the main
q
uadlock.

Also, plug the audio-20 in and meter the black fakra output to see if the standard unit is phantom feeding the aerial aswell. If it is then the DIN converter isnt sending the phantom feed and you will need a different converter. The AUX connector has nothing to do with this, nor the white connector, thats only for units that are the newer NTG 2.5 generation.


Halfords where more helpful than the forum and they did not charge me for the advice - make you wonder doesn't it....

You're not in the Diplomatic service are you?
 
Jadee said:
I used to lose my radio signal occasionally
?
Perhaps you should have mentioned that when you first posted as it might have helped.
From what I have seen you were given good advice from respected club members based on the information you supplied.


Read into what I have posted as you may.
 
No - but I was trying to be helpful by letting the forum know what was wrong with my car. The forum was not very helpful and after discussing with others outside of the forum I was able to fix the problem.

It does seem though if you post the resolution in a polite way giving the information that was sent via email rather than in a public forum you are somehow accused of being devious.

Ah well - at least I know for next time - read but do not ask questions on this site - use the other MB forum sites for dialogue where advice and solutions are free and public.
 
No - but I was trying to be helpful by letting the forum know what was wrong with my car. The forum was not very helpful and after discussing with others outside of the forum I was able to fix the problem.

It does seem though if you post the resolution in a polite way giving the information that was sent via email rather than in a public forum you are somehow accused of being devious.

Ah well - at least I know for next time - read but do not ask questions on this site - use the other MB forum sites for dialogue where advice and solutions are free and public.

Nice comeback.

You must be in the Diplomatic service.
 
With occasional signal loss and some more investigation the last faulty item has been found - the black fakra connection that swivels at the back of the radio. Cutting this off and soldering on a standard car aerial connector has made the reception superb.

Lessons learned -
1. check the connections on the back window antenna - ensure they are well fixed and there are no dirty connections in the antenna cables by removing the top and left hand side covers.
2. check the fakra connector at the back of the radio - from looking at other websites it appears that this item can go faulty.

It appears that if your central locking is working ok - e.g. from a distance - this `potentially' rules out any problems with the antenna amplifier and will help narrow down any issues.

I hope this helps readers in the future.
 
I have had a similar problem with an intermittent loss of radio signal since I tried to fix a rattle in the tailgate. From what you say it could be loose connection to the amp at top of tailgate which I did try to stick in place with double sided foam adhesive tape. Is there any particulat coloured wire or connection point I should look out for ?
Does the amp have to retain contact with metal on the tailgate since I have now used a lot more adhesive foam strips in an attempt to stop rattle and it appears I have created a new problem !
Thanks Nikki
 

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