I have a Phatnoise MP3 unit mounted in the boot of my Fabia and, for a whole variety of reasons, I had the installer run a separate cable when it was fitted, so the factory fit cable and changer are still in place under the front seat. Is there a cable or a box that I can get to allow me to switch between the two?

You could make a switch up, you'd need the same number of poles that there are cables. It would probably cause a fault code if used when the system was powered but that's nothing to worry over.

You could make a switch up, you'd need the same number of poles that there are cables. It would probably cause a fault code if used when the system was powered but that's nothing to worry over.

That's the simplest way.

Otherwise you could have a switch on a board and a few chips that would on you flicking the switch, down power to the headunit, wait a couple of seconds then switch over to the other input and allow power to the head unit again.

Would be a doodle to make as long as you can get the connectors.

Would be a doodle to make as long as you can get the connectors.

I would pay well for something like that....

Fair enough, does anyone know what part numbers those connectors are and if you can get them.

You would need to tap into the HU power and the CD interface and hopefully not much else.

Which connectors?

You would idealy need to maintain a constant feed to the phatbox to store it's settings.

I need the connectors to the CD changer/phatbox.

On the switch I would need:

A connector that goes from my box to the changer input on the headunit. Obviously I'd just need the appropriate green connector and a load of wires and then solder these straight into the board.

Two female connectors, one that would accept the above green connector from the cd changer and one that would accept the same connector from the phatbox.

Once I know they are available I could then work on wiring, working out what I have to switch and building a little board around a PIC or CPLD etc.

If anyone has anything important like keeping power to the phatbox pop it up and i'll take it into consideration when i knock a trial board up.

Also this would only switch the CD changer cables and the power switched power to the head unit on ISO connector models.

On the CAN models I'll have to work out a way to power down the head unit, do the change and then power it back up so you don't get random error codes.

You would idealy need to maintain a constant feed to the phatbox to store it's settings.

Where does that feed come from? Is it from the CD changer connector and so only on when the car is?

On the Fabia/Octy 1 you'll need to connect -

20 Pin Multi Connector Blue Section

13 - CD changer - DATA IN

14 - CD changer - DATA OUT

15 - CD changer - CLOCK

16 - CD changer - Voltage Supply Terminal 30

17 - CD changer - Control Signal

18 - CD changer - Left and Right Channel Earth

19 - CD changer - Left Channel

20 - CD changer - Right Channel

Terminal 30 is a perm live.

I don't think it's worth trying to get the 'device' to power down the HU but simply instruct the user to switch off before change over.

The connectors you need/want rather depend on where you want to mount the device. Front or rear?

I can't find an opposite connector listed for the Blue Plug 4A0 972 643 B so it looks like you'll need to use the one on the CD Changer. If somone has one of those laying around it'll have the numbers on that.

I'll have a think on what do do as pulling the switched live on the circuit is an option, otherwise it could just be a case of popping an LED on and off or coding a device that looks like a CD changer into the switch box so the headunit doesn't realise it has gone.

Do you know what data the head unit relies upon, or is it just a power to the device?

Just wondering if it reads any memory addresses.

Will have to have a proper look at this when I get some time and also get up a breakers yard and see if I can't find some appropriate changer cables.

If you need a changer cable then shout and I'll get one/two from the 'bay for you. I did suspect that this wasn't as simple as it looked.

I've not had time to look at this since I last posted but should have a bit of time this evening

Will post up my initial thoughts on here soon

I don't want to hassle you, Cheezemonkhai, but is this project dead? If you need parts then please shout as it's something I'm quite keen on getting:D

Just wondering if this got anywhere?

I'm in the situation where i want to switch between an auto changer and a connects2. It would be very nice if there is a solution as i can't decide which is be the best solution at the moment.

I've got nowhere particularly far on this as they are letting people go at work so this hit the bottom of the pile for obvious reasons.

I've got nowhere particularly far on this as they are letting people go at work so this hit the bottom of the pile for obvious reasons.

Well, thank you for what you have done, and if you ever do progress it, I would still pay well for it - say £100? and I'd cover any parts needed on top.