Radio problem & Display

I have a Citroen C3 HDI Exclusive, 57 plate. I want to keep all the radio display functions on the screen, such as radio,

MPG, Door open indicator, etc, etc, and continue controlling from the steering wheel. However, I want to use my personal

usb stick to play music.
Can I do this with an accessory for the factory radio unit?
As an option, can I connect my Pioneer DEH-X5500BT radio/cd and have the existing Citroen Siemens unit connected at the

same time, or can I simply use the Pioneer, but still have all the display functions working on the main screen.
What is the best option, and what parts do I need. I’m guessing some accessories, modifications might be needed for any of

the above.
Thank you,

Hi mike1, welcome to the forum.

You have several options,

You could add one of these: USB MP3 radio transmitters from eBay. Its a stand alone unit that accepts a USB memory stick, is powered from the cigarette lighter socket (or hard wired in with some wiring) and transmits the music to the standard C3 head unit. I have used this and it works very well. You can also find them on amazon, here (amazon link)



This takes the least wiring (none) and the least hassle, yet sounds very good.

The FM MP3 Player in a C3 top glovebox with a hardwire to the radio for power.


A slightly more involved option is this: YATOUR Car Digital Music Changer USB SD MP3 for Citroen C3 (the small box in the picture, not the thing that looks like a car stereo). (also look on eBay). This interfaces with a cable to the rear of the factory C3 stereo and behaves like a CD Changer option. Just be aware that it may be necessary to get the CD changer option 'enabled' in the car, but not always required to get the add-on recognised.



This wired option is a much more professional install, and more easily hidden away.


My third option is to remove whatever you have below the factory CD and add a new stereo to the car. Disconnect the audio connector from the factory head unit and swap it to the new stereo, tee off some power to the new stereo and you can play music on the new stereo but keep the functions available on the factory stereo.


This gives sat nav, dvd, and MP3 with a USB connection and lot more.


If you add a second stereo then the factory stalk controls won't work, you may need an extra adaptor, like this stalk adaptor to get them working, it all depends which stereo you fit.


The door open function comes from the BSI and not the stereo, same for MPG and air temperature. So this is unaffected by the radio. Some of the cars have buttons on the radio that controls the dashboard display, if you remove the factory radio, you loose access to those functions.

What is the best option, and what parts do I need

That's up to you, how much work and money do you want to spend on it? from less than £20 to over £200.

Hi C3driver52, thank you so much for such a helpful reply.
The fm transmitter would not allow control from the steering wheel stick, the Yatoyr gets reviews saying the volume and quality is not great. Also no track info.

I like the idea of adding my Pioneer under the factory radio, with a stalk adaptor. I would really like to keep all the existing factory display functions on the Citroen display screen, such as date, time, temperature, MPG, Door open indicator, etc, etc, and continue controlling from the steering wheel. I also want to control my Pioneer fully from the steering wheel. Is this how it will work, therefore the only thing which will not appear on the Citroen display will be the radio channels.

How about this which would be ideal - can I have both radios connected and all functions fully working and controlled by the steering wheel controls. Perhaps some device which lets me select which device is currently in use (as I would not want both switched on at once).

Thanks again,

continue controlling from the steering wheel. I also want to control my Pioneer fully from the steering wheel.

With the kits currently available, you can control one or the other (there is only one plug to connect to one radio). You can't use the stalk controls on both stereos without some modifications to the leads.

I don't see this as a problem as I doubt you would use the factory head unit for anything other than controlling the display - like setting the time. I think all the music will be played by the new stereo, this will be controlled by the stalk control.

I don't know which other head units can output to the display for track lists or radio information, but all modern after market stereos have their own display to show track, mp3 and radio station info.

Citroen display screen, such as date, time, temperature, MPG, Door open indicator, etc, etc,

All come from the BSI and are displayed, even without a radio fitted.

Perhaps some device which lets me select which device is currently in use (as I would not want both switched on at once).

Yes, no problem. Easy to do. Fit a changeover switch to the live supply on the radios. The changeover switch or (relay and switch combination) will allow only one radio on at a time, but the battery backup stays connected all the time.

The relay and switch combo is a better solution as it only needs a small, cheaper, light duty switch.

The fm transmitter would not allow control from the steering wheel stick,

Well, the volume is, but the tracks are not, and you don't get the screen to display the tracks either.

Parts required to choose between the stereo in use.

Change over Relay, 12v 30A (fine for 2 stereos - one at a time). A change-over relay can be identified by its five pins, as opposed to a standard relay with only 4 pins. You need the 5 pin relay.

a simple switch to control the relay, any latching 12v rated switch will be fine. One that you press and it stays switched. Not one of those that stops switching as soon as you take your finger off it (unless you wanted a more complicated circuit with a extra relay).


Some crimping tips for the relay and switch are in the link, you can also find the relay on eBay and a range of 12v switches on ebay too.

Along with crimps and another set of ISO cables to duplicate for the second stereo (which could be the iso adaptor, if you need one)

If I understand this correctly, by using the Relay & Switch, I can have the Citroen radio and my Pioneer radio both connected, both will be fully working, and both will show up their respective displays. Also, both will have full control from the steering wheel controls.
Therefore, if I switch to Citroen, all displays will be on the Citroen display, including the radio channels etc.
If I switch to Pioneer, it will work, but will only display on its facia. It wont output to the Citroen screen.

You mentioned the relay & switch to connect both devices. What about the speakers. How are they to be connected to both devices at one.

Many thanks, for your help.

If I switch to Pioneer, it will work, but will only display on its facia. It wont output to the Citroen screen.

I can't say it definitely WONT output to the car display, it depends on the stereo and what features it has, but yes, that sounds right to me.

Also, both will have full control from the steering wheel controls.

The pioneer needs to be OEM stalk control compatible (it will show on the box), and you will need the interface kit for that particular stereo and the C3. And you will need to modify the cable to run 2 stereos (as its not designed for that). You will need to modify one as they don't make these.

Both stereos can then be connected to the stalk controls, but because only one is powered up at a time, only one is controlled. The theory is good, I have never done this in practice. There is always the potential for the CAN bus to get confused, but switching off/on the ignition should clear that. I don't see you switching to the citroen factory radio very often, maybe just to change the clock settings?

What about the speakers. How are they to be connected to both devices at one.

I would just 'tee off' or 'y splitter' the speaker plugs, as only one stereo will be powered up at a time, I don't see a problem. If you do get both stereos on at the same time, you could damage the amplifiers in either of the stereos, so its important to stop this from happening. I don't think you will be driving around, switching between stereos, there is no need.

Do you really need the citroen head unit to make sounds through the speakers? if you have a nice new pioneer, why listen to the clarion/siemens/VDO/original stereo?

Many thanks, for your help.

That's OK. Its all theoretical, bear this in mind. I haven't actually tested this set-up. My personal choice would be to do away with the citroen radio, loose the function of setting the clock, radio station and track listing on the dash display but keep the stalk controls with an adaptor, while reading the track listing from the display on the new radio, its way easier.

The Citroen 'BOX' is the 'official' way to get a USB connection on a C3. This link is one on ebay, they don't come up that often and read the description where it says 'dealer programming required...'

That's really helpful.
Just one thing, if I disconnect the car battery, I'm guessing I will need a radio code. I'm not sure that I have been given one and no way of contacting the original owner of the car. Any ideas please. How many digits is it, as I have a Citroen owners card with loads of letters and numbers on it.
Thanks,

I disconnect the car battery, I'm guessing I will need a radio code.

No, no code needed.

Some tips on disconnecting the battery are here