Hi guys,

does anybody know what colour the live wire is, on the main radio plug that fits directly into the back of the radio ?

the reason i am asking this is because, i need a live supply to power the radio aerial for a chinese unit. have been told conflicting answers that its the yellow wire or its the blue wire !

thanks !

Hi guys,

does anybody know what colour the live wire is, on the main radio plug that fits directly into the back of the radio ?

the reason i am asking this is because, i need a live supply to power the radio aerial for a chinese unit. have been told conflicting answers that its the yellow wire or its the blue wire !

thanks !

Traditionally, the blue wire was always a switched live feed that only became powered when the stereo gets switched on, therefore not draining your battery at all because it isn't on all the time.

Put a multimeter on the blue wire (or even in the hole the wire comes out, you should be able to get enough on the metal inside) with the stereo off then see if it spikes when you switch it on. No reason to think it should be any different, but sometimes things do change for no reason.

Yellow is normally a live too, but it's usually power going TO the stereo not coming OUT of the it, and that's the difference. If I remember rightly, the red is the usually permanant live feed and yellow is the ignition feed: it's the wire that I normally connect in the same place as the red to bypass the ignition feed cos if you have the yellow wired on the ignition some cars/stereos only come on with the keys in the ignition, which ia a ballache.

Basically, if the stereo follows traditionally wiring, both will do it, but the blue will only turn the aerial (or cd changer, amp, etc.) when the stereo's turned on instead of it being powered all the time even when you're not using it. I know what i'd rather use.

Edited 22 January, 201214 yr by blackspaven

Alternatively take an ignition-switched live from the fuse-box.

CANBIS wiring >can< be one thing one minute, another the next!

Safest thing is to get a feed direct from the fusebox ........

Alternatively take an ignition-switched live from the fuse-box.

Same thing, just more work d1cking around in the fusebox. If the stereo's already out, i'd personally just get it from there. At least you know everything's then running under the same system & fuse.

Traditionally, the blue wire was always a switched live feed that only became powered when the stereo gets switched on, therefore not draining your battery at all because it isn't on all the time.

Put a multimeter on the blue wire (or even in the hole the wire comes out, you should be able to get enough on the metal inside) with the stereo off then see if it spikes when you switch it on. No reason to think it should be any different, but sometimes things do change for no reason.

Yellow is normally a live too, but it's usually power going TO the stereo not coming OUT of the it, and that's the difference. If I remember rightly, the red is the usually permanant live feed and yellow is the ignition feed: it's the wire that I normally connect in the same place as the red to bypass the ignition feed cos if you have the yellow wired on the ignition some cars/stereos only come on with the keys in the ignition, which ia a ballache.

Basically, if the stereo follows traditionally wiring, both will do it, but the blue will only turn the aerial (or cd changer, amp, etc.) when the stereo's turned on instead of it being powered all the time even when you're not using it. I know what i'd rather use.

Thanks for that, this may seem a silly question but here goes anyway... I have a multimeter but never really used it to test voltages, I know the red probe would go on to the where you would test the voltage, where does the black negative probe go ? Only really used it to test continuity.

Edited 23 January, 201214 yr by studmuffin

Thanks for that, this may seem a silly question but here goes anyway... I have a multimeter but never really used it to test voltages, I know the red probe would go on to the where you would test the voltage, where does the black negative probe go ? Only really used it to test continuity.

Anywhere where there's an earth or bare metal if you need to do that. I haven't needed to use mine for ages so kinda forgotten how it works! lol. IIRC, mine has a setting where you CAN just put the red probe on something and it'll tell you if there's a feed, but mine is a bit all singing and dancing.

If you need to find a cable to earth to, if it's in the stereo block the earth is traditionally the black wire, and if you need one elsewhere on the car, brown is mainly the earth with occasionally it being black but not very often. I may, MAY have gotten the red/yellow the wrong way round in my earlier post though, but i'm pretty sure the red is the constant live.

So basically, chuck the black probe on the metal bit of the black cable where it goes into the rear of the connector block (should be able to do that, there's normally enough space to wedge it in), then put the red probe on the red, yellow and blue cable metal bits in the housing one at a time, with the ignition and stereo switched on. If i'm right, what should happen iiiiiiis...

The red should work all the time as it's straight to the battery

The yellow should work only when you switch the ignition on

The blue should work only when the stereo is switched on

By switching stuff on and off, the readings should be able to confirm the above is correct and then decide how you want to wire it. Even if it's wrong, you're not gonna blow anything by taking readings from any of the wires in the back of the stereo housing cos you're not making a circuit, as such, so fill your boots!

Please bear in mind this is usual for a standard aftermarket headunit. Not quite sure how it works (but could probably work it out if I could be @rsed to take the unit out and have a butcher's), but the OEM units switch on and off when you put your keys in, BUT they can also be switched on again once the ignition has been turned off without having to turn the ignition on again, which is handy, nothing more.

Hope that helps.

Edited 23 January, 201214 yr by blackspaven

Had a quick google, and it looks like Skoda choose to colour their wiring a selection of drab greys (your aftermarket h/u WILL probably be the colours I said), so this might give you an idea of what to wire stuff up to...

http://briskoda.net/forums/topic/43971-ice-iso-connections/

Having said that, as I said before, you can't hurt anything my testing with your multimeter just to make sure.

There is NO ignition live wire at the back of the stereo in the Octy. Only a permanent live.

The headunit is signalled on/off over the CANBUS rather than the traditional perm live/ign live method.

If you want a proper ignition switched 12v supply it'd be easier (and safer) to run a wire to the fusebox. It's easy to do and doesnt take long.

There is NO ignition live wire at the back of the stereo in the Octy. Only a permanent live.

The headunit is signalled on/off over the CANBUS rather than the traditional perm live/ign live method.

If you want a proper ignition switched 12v supply it'd be easier (and safer) to run a wire to the fusebox. It's easy to do and doesnt take long.

If I was fitting this though, I wouldn't want it wired to the fusebox, i'd want it wired to the stereo to only work when it comes on, otherwise you're powering something that's potentially redundant. I figured that's what he wanted to do as this is the normal operation for an aerial. Never heard of it being wired otherwise for the reason I said beforehand.

If you know the wiring behind an octy stereo, which pin is live only when the stereo is switched on then? If it DOES have that coming out the back, it'd only be used for that purpose, and power would be reliant on the stereo, not the canbus.

Old school wiring was much easier!

Edited 23 January, 201214 yr by blackspaven

Now to throw something more into the equation

I have the Columbus fitted to mine, works as it should with the ignition on or off.

I also have a freeview box fitted but its powered from the fuse box

To watch TV I have to have the ignition on (all lights on the dash on)or the engine on tick over, I dont when listening to the radio or playing a DVD, as the key is in position 1, position 2 puts all dash lights on, position 3 starts engine

Is there a way of wiring the freeview box so that it will work with the ignition in position 1

Sorry, too tech for me, i've not got behind the dash of an octy (yet), just golfs and other older motors.

Anyone no which fuse is the best one to use to get a switched live for a aftermarket head unit. As at the moment my head unit will only power up if I put the red wire directly into the live feed which is on the original wiring, this works but will permantly stat live Untill the battery dies... And also where would I put the orange wire off the look which is used for the illumination? 
many thanks 

see second post , yellow is/was then switched live