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Becker CDR23 Connections

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Hi I know there's been lots of posts over the years about connections to the CDR23 , but reading through them I can't see an answer to my puzzle.


My car is a 04 plate 2.7 with just the front speakers in the dash , so no door speakers and no rear speakers , no cd changer and no amp. It's not a Bose system.


i have just added two rear speakers and taken the speaker wires to the ISO connector where the front speakers are also connected. This works.


i found when the unit was out that there is a connection to the yellow c1 plug which according to the wiring diagram is a line out , however line out to what ? Also not all the pins are connected , 


heres a picture , first time on the forum so hoping somebody can tell me.


thanks steve



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  • 2 years later...

Thanks for that information guys, but does anyone actually know what those 4 wires do?......


Yellow -  CAN Comfort High

Black -  CAN Comfort Low

White/Red - Wake up/Diagnosis Line

Green - Key Code In


i.e. what is CAN comfort, what is the wake up for and what is the key code in for? I can’t find any explanation of these anywhere. 
Thanks in advance,



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  • 1 year later...

Good evening, 

I have exactly the same set up as you and will also be adding some speakers in the rear parcel shelf, bit more of a surround sound rather than a blasting from the front. Adding speaker wires to the brown connector is the plan, seems logical. 

However, I'm trying to work out how to change the CDR23 in mine to an after market head unit, but the yellow C1 connection is throwing me off... 911 design do a number of wiring harnesses, but none seem to fit the most basic initial stereo set up (no amp, no CD changer, not Bose and only the dash speakers) 

Would love to know which, if any, of those C1 wires have to be used to power the aftermarket unit as I can't seem to deduce which is the ignition power to the unit. 

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Hi Aramis. 
The Yellow C1 plug is not for power in the configuration for my car. 
As Richard stated:

The 4 wires connected to the yellow plug are:

Yellow - CAN Comfort High

Black - CAN Comfort Low

White/Red - Wake up/Diagnosis Line

Green - Key Code In

The BLACK connector should have the power and earth wires that can be used for the new head unit, as per the diagram attached. Hopefully this helps. 


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Thanks for the info, I managed to get the aftermarket stereo in, used a wire straight from the fuse box which was connected to an ignition fuse, then to the back of the stereo, loose some of the nice functionality of the yellow C1 plug (stereo staying on until key is removed) but the output from an after market is so superior that this doesn't bother me. 

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Hi Aramis. Good to hear that you have had success. I take it that you connected the yellow wire on the new head unit to that fuse? Sounds like you need to connect the (normally red) ‘accessory’ wire on the aftermarket head unit to that switched 12V line instead, with the yellow wire going straight to a constant 12V line to solve that problem. The head units often have a yellow wire for constant 12V - you just need to know which of the old head unit wires was unswitched (always on) and connect that one as well. Hopefully this helps. 



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