1996 R129 SL500 stereo - installing Mercedes head

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tombobo

New Member
Joined
Dec 7, 2004
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13
Location
Basingstoke
Car
1996 R129 SL500
Hi guys

I've had my 96 R129 for about 6 months and now the weather is starting to improve I'm starting to do some jobs which have been on my list of things to do since I got it...

First of all, I appreciate that there are a lot of topics on this. I have done a lot of reading through past posts but can't quite get the answers I want...

The car had an alpine head unit and multi stack changer in it which I have now taken out. I've bought an audio 30 head unit and mc3198 cd changer which is slightly newer than should be in the car but I think is a good compromise for the looks and has sat nav functionality.

After a lot of pulling of the alpine wiring harness I found the original Mercedes wiring harness. This has plugged straight into the audio 30 which powers up and works with no issues. However, there are a couple of questions about it I'm hoping someone can help with...

There's one cable remaining from the alpine harness which doesn't go into the Mercedes one at all and goes straight into the centre console. This is labelled as "audio interrupt in lead"... is this something that should go into the Mercedes harness and if not, any suggestions for what to do with it? The cable is thicker than the MB wiring so I assume it's an aftermarket addition?

Additionally, the Mercedes harness appears to have had one cable cut and then jointed to another. A photo is attached but not very clear. Is there any reason this would have been done? Can someone provide the connector wiring diagram to assist?

Harness aside, the next question is about what wiring would have originally been in the car for a cd changer? There is one cable which looks to be a fibre cable but is a different fit to the mc3198 fibre connection. Was there a previous cd changer which used this type of connection? Photo attached again. I'm aware that I will need to run a new cable to use the mc3198 so, if this existing cable would work with an older changer I might change course and revert back to an older head unit / changer. The other end of the cable does seem to be present in the cd changer position in the boot too (don't have a photo of this at the moment though)

Thanks guys
Tom
 

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Welcome, Tom. Yours is post-facelift, and it may well be a bit different, but on my 1994 SL500 the audio wiring harness connections are:

OE loom wire colours and functions as follows:

Thick Brown Earth

Thin Brown (x 2, in a 5x2 connector) Boot CD changer

Red/White (thick) Permanent live 12V

Grey/Blue (very thin) Instrument Lights

Black/Green (very thin) VSS/GALA (if fitted)

Black (x 2) Speaker Negatives

Black/White Left Speaker Positive

Blue Aerial

Green/Black (Thick) Right Speaker Positive

Black/Blue (thin) Switched Live 12V

I hope this helps.
 
Hi again

A few more photos...

From what I think I understand from research - the C connector (?) appears to have wiring which would suggest originally there was an me cd changer? It's got 9 connections to it... are some of these power? I can't seem to locate any power in the boot.. I've got suspicious it may have been pushed out and is now lose somewhere... photo is attached.

Also I've attached a photo of the other end of the fibre type looking cable... can anyone confirm what this is?

Thanks
Tom
 

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Hi guys...

Anyone offer some advice?
 

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