MP3 Input for CDR2005 Radio and CD Unit

About: Passionated about electronics, robotics, software and Chinese Arts

Hello everyone,

When your car is 'as old as mine'. I doesn't have an MP3 input. Oh, there are a lot of converters you can buy if you have a recent radio with an external CD changer connector on the back of the radio. You can guess that I wasn't that lucky as well, damn old radio! But old radio's have one advantace: there is always someone who has had the same problem, actually there were two.

First of all:  I am writing this tutorial because my board layout of my Radio and CD unit was totally different then the only described today (4th of July 2011). The adapation I am suggesting is quite invasive! It involves opening the whole unit, removing the CD unit and cutting through a bus connecting the CD unit and the motherboard of the radio unit! It's like open heart surgeon (euh, of course with the current unplugged :p).

The tutorial is quite specific: for people who have a CDR2005 (non VDO version) and want to play surgeon with their unit ;-)

For people who have CD2005 VDO I would like to guide you to the Unkown Soldier .
In general I would like to recommend Jason Novak's thread .

Secondly -I think you know the drill-: I am not responsible in any way for any damage or other to your radio, car, mp3player or any other thing or person. You will lose the guarantee of your CD unit and on the it's quite possible that your garage owner will kick your ass if you have to beg for help ;-)

Step 1: What You Need

What you need:

- Decent Torx screwdrivers and other soldering/cable tools
- The Radio Code -if you remove the radio it is automatically secured with a 4-digit anti-theft PIN code- && The Radio's manual to read how to unlock your radio with the correct code.

General notice:

Keep track of all the screws you have to remove. Remember where they came from and if they differ in size/length. I took dozens of pictures and labeled all sets of screws and pieces.

Step 2: Remove the Unit

Remove the Radio and CD unit (RACDU): you have to loosen the bolts in every corner. Then you can insert the removal tools (or you buy them, or you can make them yourself: be warned - - - the self made tools can scratch your radio if they don't fit well).

You can find a good instructional video here .

Step 3: Remove Plates

Open the RACDU and remove the top and bottom plate.

Step 4: Unscrew and Remove the CD Unit

When the top plate is removed, you can see the CD unit (CDU). Screw the CDU out of the RACDU.

Turn the CDU upside down. The bottom contains a shielding black plastic. Under the plastic you can check the board number. It should be E-827SA-1 (see here). If you don't have this number I can't advice you because I've only tested it with this motherboard!

Step 5: Surgery

You will see two bundles of cables connecting the CDU and the radio's motherboard. One bundle contains two wires (black and grey). Another one contains 14 wires (13 red ones and one blue). You have to cut soon so keep your tools ready! Taking the 14 wires bundle. Counting from the left (with the blue wire on the most right = number 14). You should cut the 1th red wire (which is the left audio channel) as well as the 3th red wire (which is the right audio channel).

The principle is easy: you will reinstate the 1th wire and the 3th wire with a switched 3.5mm jack (normal closed switch). When a jack is inserted, the switch will disconnect the CDU from the radio's motherbord and feed the jack's audio to the radio's motherboard. As easy as this. Read more here.

Using a UTP CAT5 cable is very handy like suggested in the post. I broke out with the wire at the bottom (because it's the only side where there is space enough!). Therefore I had to drill a 6mm hole in the bottom and carefully removed any metal burrs! Make sure you don't short circuit anything! Even not to spill any drop of solder. If it resides in your RACDU, I won't like to be in your driver's seat when the radio just stop playing.

I suggest to use heat shrink tubing to shield the solder as well to make it more pretty.

Step 6: Test If the CD Unit Is Still Working

At this step I've already restored the 1th and 3th wire by just connecting the corresponding UTP-wires at the and of the UTP-cable to test of the RACDU was still working.

After putting the CD unit back with the hooking clips and entered the coded I've tried to play a CD and... it (stil ;-)) worked!!!! Wihaaaa!

Step 7: Location for MP3 Input Jack

After hours of looking, measuring, looking again, lighting into every tiny space under every plastic board every corner of my car, looking and measuring again I decided to put the jack into my lower dashboard (close the the back window heating). I've considered other locations as well which were all dropped:

- front ashtray: it seemed unhandy to put in a audio cable in the rather deep ashtray

- back ashtray: dropped because the quite limited space on the one hand and the too big distance from the driver's seat.

- space around and near the car cigarette lighter: dropped because there seemed to be two square 'connectors' (don't know the use) underneath that space. One at the left and one at the right. I could manage to push a jack (with a bit bending of the legs) between the lighter and tje 'connector'. That seemed rather ugly and I was kind of afraid that it maybe would detoriate fast due the heat when using the car cigarette lighter (however I don't smoke haha).

- top right/left of the gear lever: dropped quite fast. The jack will fill with dust after a while which will give bad electrical/conductive connections on a long term (especially important when dealing with audio).
I found a good spot where I wanted to drill the hole for the jack. I've checked it probably fourteen times against my car. You have to be careful here because there are a lot of pins and plastic peaces around the knobs. Check enough that your jack can still fit in the supposed space when the dashboard is in place as well!

Step 8: Holding Your Breath

After this you should exercise how to hold your breath! Drilling into your car's dashboard is extremely hard to do! 

Then I could finally shorten the UTP cable at the right length. Take into account that you should be able to remove the CDARU while the jack is still into place in the dashboard. Make the cable long enough to work handy as well.

The lower dashboard (where the on/off buttons resides for the back windows heating) contains a very hand hole wherein a UTP cable can fit through easy! I fixed the UTP with hot glue so that the buttons don't rub or scrub the cable sheathing. I deliberate placed it to the right of the buttons because it's more convenient that it's at the passenger side as well that I wanted the left space untaken for maybe a future USB charging port. 

Step 9: Finished!

In the end, it all worked! I was kind of amazed :-)))

Have fun!



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4 Discussions


4 months ago

A very good tutorial, but you don't tell and show us how to install the input jack.
I mean: how to connect the wires to the jack plug.


10 months ago

Hello, i have tried this tutorial on my opel Omega B facelifted and it works perfectly Thank you to author. This way has a major advantage, you can keep access to you CD unit in use !

i have to notify you that my Autoradio mother board is not

E-827SA-1 ( As described in this tutorial) but it's E-827SA-2. So it mean that if you follow scrupulously this tutorial, it will works, no matter if your motherboard is E-827SA-1 or E-827SA-2.

Thanks again.


1 year ago

Thanks for the instructions! I just bought a Corsa C with this radio
and the mod works perfect. I used a plug without a switch so I can't listen to
cd's but that’s no problem for me.


1 year ago

hello dear friend, or anyone who did this. i tryed and done everystep as said... but still dont work. can you help me please?