Lights on Radio on, Lights off radio off

[Ghost_2008]

Hi Guys,

I have fitted a new stereo head unit, previously the car had a Sony Head unit, which was a cheap replacement for the previous owners expensive bit of kit. Anyway finally got round to buying a lovely Pioneer replacement. Fitted it and all went smoothly. Tried to turn it on and no luck, so I had a further fiddle and hey presto it seemded to come on and work perfectly.

So the next time I get in the car I cant get it to come on which I thought was very odd, turned the lights on, tried the radio again and on it came......:inquisiti

I guess that the harness for the Sony is not an exact fit and the pin arrangement must be slightly different, but essentially if I swop the perminant power supply and the 12v switch, would this resolve the problem???

yellow/red = right rear spkr +ve
grey/red = right rear spkr -ve
yellow/blue = left rear spkr +ve
grey/blue = right rear spkr -ve
white/black = signal (annt)
white/blue (thin wire) = not sure!
blue = +12V switched
red/black = +12V permanent (memory)
green/white = lights
black/yellow (thin wire) = not sure!
white/blue = left front +ve
black/blue = left front -ve
white/red = right front +ve
black/red = right front -ve

Thanks for your help guys.........

[Turbo_Steve]

er...are you sure it's the +12v and +12v switched that are the wrong way round, as normally just turning the ignition on will resolve that. It sounds more like your headunit is trying to run off the "Illumination" feed....where it will definitely draw too much current!

Do you have a converter fitted, to bring the factory loom out to ISOs?

The harness that comes with the headunit has to stay with the headunit: they all use proprietary pin outs. If you did reuse the Sony harness with a Pioneer headunit, you're very lucky if it didn't do any damage!!!

[Ghost_2008]

I used the Pioneer harness which was supplied with the head unit and I used the "halfords" adaptor from the Legnum wiring to the Pioneer wiring which was previously use with a Sony head unit (if that makes any sence). All the electrics work fine. The pin layout in both the Sony harness and the Pioneer harness matched up, so I assumed that it was a straight fit.............

[HMG1K]

Ghost_2008 - sounds stupid and simple, but this happened to me last Christmas.

I bought a brand new loom for my 1996 Kenwood headunit to fit in my 8G Galant (as my last 6G Galant wasn't an ISO style so at the time I had to connect wire to wire). I then bought the Kenwood to ISO converter cable from Halfords and had similar hassles.

The problem turned out to be a faulty ISO loom from Halfords. I took it back, got a new one to try out with one of the assistants in the car park and BINGO the new one worked a treat!

All of Halfords radio parts are sourced from this company http://www.autoleads.co.uk/ and Halfords then own-brand them.

[Turbo_Steve]

As HMG1K says, the connectors that are the same between the Sony and Pioneer harnesses are called ISO connectors and are a "standard" way of connecting car stereos. Handy. Except, as you suggest, the Permanent live and Switched lives are sometimes reversed.

Just to be clear: Your headunit only works when you turn the lights on?
It doesn't work with everything switched off.
It doesn't work with the ignition switched on (i.e. all the little warning lights in the dash glowing, as though you were about to start the engine).

Does the headunit lose all it's settings (stored radio stations, place on CD etc) when you switch the ignition & lights etc off?
How about if you leave the lights on, but turn the ignition off?

It sounds to me like the ISO adaptor you have has the Illumination pin and Switched live pins reversed.


HMG1K...how was it faulty - Manufactured with wires in the wrong holes would seem the only possibility, as there isn't a lot that can go wrong on these :)


One last thought: Is the headunit earthed properly? Take a flylead from the chassis of the headunit to an earth point behind the dash. I suspect this isn't the problem, though, as no earth usually results in not working at all.

[HMG1K]

HMG1K...how was it faulty - Manufactured with wires in the wrong holes would seem the only possibility, as there isn't a lot that can go wrong on these :)

Exactly - there isn't much to go wrong with six or so wires in a block!

It was a memory hassle with the presets not being stored. Seeings I hadn't done an install for 18 years that tiny thing, after everything went fine, almost threw me.

It must have been a mis-patched / one faulty connector - but I was so pleased when in the car park of Halfords with the assistant on hand allowing me to try a new ISO converter it worked perfectly.

[Ghost_2008]

Thanks for the replies guys, the ISO connector must have some wires switched, the settings all go when the lights are switched off, it doesnt come on unless the ignition and lights are on........... I think the best thing will be either buy a new ISO or try to swop the wires about.......... red/black = +12V permanent (memory) & green/white = lights, seems to be switched, so best case senario would be switch these back and hey presto......... I'll let you know what happens.... thanks again

[Ghost_2008]

Just to let you know I removed the radio and checked out the pin layout, literally relocated a pin to the hole above and bobs your uncle...... The battery supply was below where it should have been to marry up to the radio harness, however it worked perfectly well on a Sony unit. I thought they were all universal adaptor? As you go into Halfrauds etc and say can I have an ISO cable for a Mitsubishi Galant/Legnum and regardless of the stereo brand they only stock one unit..... It didnt cause any damage and everything seems to be working fine but I guess it could have been a lot worse...........

[HMG1K]

Nice one! Glad you've got it sorted - see, simple misplace of wire at manufacture and a massive hassle!

[Turbo_Steve]

Hooray. And, it depends, the Sony may not have used that particular power line for anything: whilst the pin-outs are standard, some kit chooses not to use some of the functions. If you look at the connector, there are a load of pin holes not populated. These are all reserved for use by Sat Nav, Reversing camera, all sorts. The only car I am aware of with a "Full" ISO implementation is the Audi's, which have all 5 connectors.