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Wiring a headunit?

Discussion in 'ICE, Sat Navs & Dash Cams Forum' started by Grease, Sep 22, 2005.

  1. Grease

    Grease
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    Recently got into a fight with my current installer bloke, who now won't answer his phone to me, so I have to install my nakamichi headunit myself...Problem is, I don't know how to! All i know is he has done it differently, the ISO plug etc has been chopped and he has used terminal blocks...

    What do i do? argh!!
     
  2. lynx

    lynx
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    No competent installer would simply cut the loom :confused: Try and repair it with something like...http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=CP02772&N=0
     
  3. Ayub

    Ayub
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    if you could take a picture of the wiring loom and post it here or to my mail i could tell you.
     
  4. ryder_4

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    hi, seems i have the same problem, and old car with wiring that makes little sense to me. Ive got my iso connector and i thought it would be pretty easy to wire up but i dont know what the individual wires mean. its a peugeot 306. Ive got a pic that i'll mail you. and what i do know is that the thick white (already connected to the red) is the power (ignition switched i assume). The red (connected to the green) is the back right speaker (fairly confident), and the large green (not connected) is the speaker common. Im not sure which one the earth is. i tried using the speaker common as earth but it didnt work.
    cheers
     
  5. ryder_4

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    heres the pic
    when i took out the old radio the orange wasnt connected and neither where the two twisted bundles of 3 (which i am assuming are the front speakers which didnt work) dunno why there would be 3 wires though.
    any help would be much appreciated
    thanx
     

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  6. seven48

    seven48
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    Thats a mess! Any good installr would not do that with those connectors.
     
  7. spl23

    spl23
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    The manual for the Nakamichi should explain the colour coding of the wires at its end - assuming it isn't just a standard ISO connector. If not, Nakamichi ought to be able to provide you with the require information.

    The wires going into the car loom look a mess! First, get hold of a multimeter - a cheap one for a fiver from Maplin will do.

    You need to find the power connectors first. Connect one probe on the meter to a chassis ground (i.e. a screw on the bodywork), set the meter to resistance, and touch the other probe to each wire in the loom in turn until you find one which has zero resistance between it and the bodywork - that's your ground wire.

    Set the meter to volts, connect one probe to the ground wire you just found, and with the ignition off, touch the other probe to each wire in the loom in turn until you find one which has 12V on it - that's the unswitched 12V.

    Turn the ignition on, and repeat the above - there should now be another wire with 12V on it - that's the switched 12V. Make sure that one drops back to 0V when you turn the ignition off.

    OK, you now have 3 power wires. Make a note of them. Now get yourself a 1.5V battery, and sort through all the other wires. Take pairs of wires in turn, and for each pair, first check with the meter that there is no voltage across them. (If there is voltage, move on to the next pair.) When you find a pair with no voltage, touch one to each end of the battery, and listen - if these are the wires for a speaker, it will pop loudly when you do this. (Don't leave the wires on the battery - just briefly touch them - or you may damage the speaker.) Do this until you've located all 4 pairs of speaker wires.

    You may have an illumination connection as well. To find this, turn on the headlights, and with the meter on voltage, connect a probe to ground and touch all the remaining wires in turn until you find one with 12V - see if this turns on and off when you turn the headlights on and off.

    Finally, there may be a power antenna connector in the loom - this will probably be the only wire left at this point! If not, finding it will be awkward, as it involves applying 12V to wires at random until the aerial extends - not to be recommended, as you may damage something.

    The above is one way of finding out what on the loom does what. It's reasonably simple if you know what you are doing, but if not, try and find a friend who understands about how to use a multimeter and basic auto wiring.
     
  8. ryder_4

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    your an absolute legend, what you have just written is what i was searching for ages on the net, either i was looking in the wrong places, or somebody hasnt designated a space for this invaluable information (other than in forums of course)
    i shall let you know how i get on, seems strange how little standardisation there is on slightly older cars, a friend of mine also mentioned getting a multimeter, reminds me of physics at school. im sure i'll manage though.
    just realised that some of those wires will be the remote stalk and im assuming that they will read 0volts and there wont be a 'pop' cos theyre not speakers. and my car doesnt have a power antenna.
    cheers
     
  9. spl23

    spl23
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    One thing I ought to add...

    You'll do no harm connecting a multimeter on either resistance or voltage across any two wires in the car - you may get some odd readings on resistance if you connect it across a voltage, but you shouldn't break anything. However, DO NOT connect a multimeter set to measure current across anything in a car - that converts the meter to a dead short, and you will, at the very least, blow fuses somewhere, if you don't melt part of the loom or the meter.

    I also ought to add - when testing for the speakers, it's a good idea, before applying the battery, to use the meter to check the resistance across the pair of wires you're about to try as well as the voltage. If your meter is sensitive enough, it should show about 4-8 ohms when across a speaker. If it shows 0 ohms, don't connect the battery across that pair, or you'll flatten it fairly quickly! In fact, thinking about it, just putting a meter set to resistance across a pair of speaker wires will probably make the speaker pop audibly - you shouldn't need a separate battery.

    I've got no idea at all about finding remote control or remote display wires - I think you may need more than a meter to work out which are those, but you are unlikely to do much damage if you follow the procedure I described above. Be aware, though, that I'm only listing what has worked for me in the past - it may not be the recommended procedure, and you do it at your own risk! In particular, be very careful not to accidentally short wires with 12V on to ground (as they will melt very quickly if they aren't properly fused), and don't short 12V across speakers, as the voice coil on the speaker will melt (and you'll probably tear the drive cone surround as well if you're unlucky).

    It really is worth finding a competent auto electrician to give you a hand if you are in any doubt about the above - you can't give yourself nasty shocks with car 12V wiring, but it is quite easy to set stuff on fire!
     
  10. ryder_4

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    thank you again, cant believe it..... £2.89 for a multimeter at maplin. sure beats £40 at halfords for an installation. off to the driveway...
     
  11. ryder_4

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    all done, im a happy boy now thanks very much. things are so easy when you have the right tools. i recon reason for the horrible loom is that my car may have been broken into and the wires cut. hense the different locks. hopefully the car will be luckier in my hands. thanks again, i can now install better front speakers and enjoy one of the best bits of driving..... music!
     
  12. spl23

    spl23
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    Well done! Glad it worked out for you - and that my instructions didn't lead you to set the car on fire (or worse)...
     

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