UK-POLOS.NET - THE VW Polo Forum

Hello, I have a Polo 6N and a Sony CD Head unit, but I want it so when I turn ignition the CD starts playing, at the moment when you turn the ignition the power is already at the head unit and you have to press SOURCE for the cd to play, but if you turn the head unit OFF when you turn the ignition nothing happens, get what im trying to say? lol its like you manually have to give the head unit power.

I’ve read in the Sony manual that the car has to have ACC power has the polo got this?

Thanks

Andy

Hi how have you wired it up, if you've used the VW iso connector it will be wrong for the sony headunit
this may be of some help http://www.installdr.com/Harnesses/VW-Wiring.pdf either that or buy the iso converter leads from Halfords about £14 IIRC

i'm a bit confused by what you want the head unit to do, could you explain it again?

i've got a tape one that i had in the polo which did similar things.. there's a switch on it somewhere. (part of why my battery kept running down is that i set it to be continually on, as it lost the memory settings otherwise.... probably because of not having it wired up right )

Hi thnx for replyin, yeah im using one of them ISO converters from halfards but still seem to have the same problem, i tried swopin the RED and Yellow Bullet things earlyer but nothing changed any ideas? thanks

Tahrey1043 wrote:i'm a bit confused by what you want the head unit to do, could you explain it again?

i've got a tape one that i had in the polo which did similar things.. there's a switch on it somewhere. (part of why my battery kept running down is that i set it to be continually on, as it lost the memory settings otherwise.... probably because of not having it wired up right )

What i want the head unit to do is, when i switch the ignition on the CD/Radio should auto come on.. but it doesnt you have to press SOURCE that then switches the CD player on, although there is always power to the head unit for sum reason i have to switch it off using the OFF button even when you turn the igntion off it stays on .

(sorry if that dont make sense bit knackerd bin work all day ) lol

thnx

the ISO connector from halfords will sort this out.

£13.49 when i bought it.

carmadaaron wrote:the ISO connector from halfords will sort this out.

£13.49 when i bought it.

I already have the halfords ISO connector still have the same problem tho, is there a setting u have to change on the head unit?

thanks

i have the same problem too and am also running an sony cd /mp3 headunit. Did u or do u have an aftermarket fitted alarm or remote central locking kit in ure car? basically mine was taped into for one of the alarms functions, but as my alarm was disconnected this wire was badly d/c - u may have something similar possibly. I need to sort this out too, which i havent already done, but im planning to sort it in the next couple of days.

it could be this or the switch for the acc in the ignition itself that is gone. or it may also be a faulty hu

But if its just the wire u can simply re wire the yellow wire or put a new one in by tapping into the ignition wire and using this instead. Ill try n explain it a bit better once ive done mine though mate.

Hi, yeah let me know how you get on, although ive got no alarm or remote central locking in mine.

Thanks

i never did figure it out, but removing the faceplate drops the power consumption quite a bit - if it wont turn properly "off" that might be the key.

could just be sony being arsey and non-standard as is their remit. did you get a load of the control system on the Hi-MD players? does my head in.

ok definitive answer to this problem for one and all:

there are three main power wires on the back of most head units. ISO is a wiring standard used by the car audio industry that dictates these wires should behave in the following way:

yellow: direct live 12Volt feed. (i.e. permanently connected to positive terminal of the car battery- permanently live)

red: ACC wire. "switched" feed. This wire should run off the ignition and only become live when you turn the key

black: earthed cable to chassis of the car.

(ignore other cables for purposes of this post)

the reason for a permanent live feed is to hold settings on the head unit such as radio presets, bass/eq settings etc. These setting are therefore held on the head unit through the power provided to the yellow cable.

The switched cable is to let the head unit know that the key has been turned and therefore there is power to both cables so the headunit can power on.

If you get these cables the wrong way around, then there is no permanent power to the unit when the key isnt in the ignition, therefore settings wont be held. also, the unit wont have a switched signal either- so no auto turn on/off.

the halfords adapter works- but is pretty much a rip off. On some cars the original wiring looms are VERY different to the ISO plugs (toyota, honda etc being good examples) on VW however (in general) they are near enough the same- same size plugs, identical speaker plug etc. the ONLY diffference is, for some stupid reason- VAG decided to put the live and switched cable the wrong way round!!!

most new head unit original looms have bullet plugs built into them anyway- so rather than buying the halfords loom for £14, swap the bullet plugs on the red and yellow cables which are on the wiring loom for the head unit itself. if there are no plugs then just cut those two specific cables (no others- just red/yellow) and bullet plug them using crimpers and bullets then swap them over as already stated.


sounds complicated but its probably because ive explained much more than is need- basically swap the red and yellow behind the head unit and will solve the problem- near enough all volkswagen,audi,seat and skoda are like this.