EnglishRob 0 Posted October 12, 2008 Hi folks, I was wondering if anyone has details of what wires are what for the wiring on the head unit? I've been trying to properly fit my head unit in my 205 today and I discovered the previous owner was a cheapskate and just chopped the original head unit connector off and stuck an ISO connector on there. Now the head unit appears to work okay apart from the dimming of the headunit when the headlights are on. I just wondered if anyone knew what colour wire is for the lumination, or even the wire number? (I must get a Haynes manual!). (BTW, I have done a search and can't seem to find anything specific, maybe I'm not using the right keywords?) Ta, Rob Share this post Link to post Share on other sites
jeremy 71 Posted October 12, 2008 IIRC there is'nt one, so you would need to take the feed from the light stalk, any instrument lighting wire, or possible the dash light dimmer mounted under the steering wheel. Share this post Link to post Share on other sites
DrSarty 90 1 Cars Posted October 12, 2008 I have two points for you. One is, why bother? Do you REALLY need them to dim? IF you really really must, as Jezza said, common sense says that your head unit's 'headlight sensing' wire, is just waiting for a 12v live feed that comes on when the lights are turned on. So as he suggests, you could just tap into any wire going to a dash switch illumination bulb and connect it to the wire on the head unit. You can test this out of the car I would've thought too, by giving the head unit an earth and a live so it turns on, then touching that HU sensing wire to a 12v feed and seeing if the HU dims. The ONLY risk you have, is that I'm not sure whether that head unit wire senses 'lights on' either by receiving 12v or being grounded. Personally it'll either work or it won't, or it may trip the fuse. My gut feeling is it wants a 12v live; but you'd best check. Share this post Link to post Share on other sites
EnglishRob 0 Posted October 12, 2008 Hmm, good point. I haven't got the manual for the head unit (it's an old Sony Mindisc headunit). I'll do a bit of Google searching before I attempt it. Last thing I want is to blow my head unit up. Rob Share this post Link to post Share on other sites
Phil H 16 Posted October 13, 2008 I'm sure the headlamp wire is at the radio connection. Mine is standard wiring and the headunit lights up behind when you turn sidelights on. Just get in there and probe the wires on the iso and see if you get any joy. Worst case scenario is take a feed from a switch above. Share this post Link to post Share on other sites
Baz 421 Posted October 13, 2008 It is, i've had plenty of 205's with stereos that dim when the lights are on. Don't ask me how it's wired though! Share this post Link to post Share on other sites
Super Josh 4 Posted October 13, 2008 Yep, it's a +12V signal from the sidelight circuit. If it is missing, just take a connection from the clock Josh Share this post Link to post Share on other sites
jeremy 71 Posted October 13, 2008 Yep, it's a +12V signal from the sidelight circuit. If it is missing, just take a connection from the clock Josh In my experience if your clock works including the illumination of it, then leave it alone, as they seem to be very tempremental. Share this post Link to post Share on other sites
shalmaneser 26 Posted October 17, 2008 my sony headunit just has a setting that does it automatically. I guess it senses the voltage drop when you put the headlights on. You need the remote to program it though - and i've lost mine! Share this post Link to post Share on other sites
jackherer 543 Posted October 17, 2008 my sony headunit just has a setting that does it automatically. I guess it senses the voltage drop when you put the headlights on. You need the remote to program it though - and i've lost mine! Are you sure its not activated via a wire or maybe it has an ambient light sensor? Thats how my satnav knows to go dim. I would have thought if it works from a voltage drop it would dim when the heated rear screen goes on etc. Share this post Link to post Share on other sites
shalmaneser 26 Posted October 19, 2008 Are you sure its not activated via a wire or maybe it has an ambient light sensor? Thats how my satnav knows to go dim. I would have thought if it works from a voltage drop it would dim when the heated rear screen goes on etc. it certainly doesn't have any other wires apart from those that come out of the iso connector - nothing that needs splicing in or anything. Doubt it's down to ambient light because you can see the screen light up and dim down about a second after you turn the lights on/off. Always just sort of assumed it sensed the voltage drop, but got no proof but it still seems the obvious way to do it...although now you mention the heated rear screen i'm a little less sure Share this post Link to post Share on other sites
large 33 Posted October 19, 2008 it certainly doesn't have any other wires apart from those that come out of the iso connector - nothing that needs splicing in or anything. Doubt it's down to ambient light because you can see the screen light up and dim down about a second after you turn the lights on/off. Always just sort of assumed it sensed the voltage drop, but got no proof but it still seems the obvious way to do it...although now you mention the heated rear screen i'm a little less sure You will find that it is the orange wire on the iso. Share this post Link to post Share on other sites
