THE GREY WIRE CONUNDRUM...

Discussion in 'Mech Tech' started by JAFFA, Aug 23, 2020.

  1. Hi Folks...

    After long ongoing restoration 73 bus... sorted all the electrical stuff as it should be and everything working fine and dandy...

    Was left with two wires in the centre of dash emerging from the cable loom... one grey and one brown... with no obvious home... presumed these were for the radio... brown is ground... and the grey appeared to be a constant live...

    After connecting up the new stereo using the grey presumed constant live and a live through the ignition as required... was a bit perplexed as to why the stereo was dead...

    Turns out the grey wire is live when the ignition is off... and dead when the ignition is on...

    The wiring diagram used is correct in all other aspects, but does not show this wire as far as I can see and shows no listing or wiring for a radio...

    Can get the stereo working through other means but... what could this grey wire be doing?...

    Any ideas welcome...

    Ta...
     
  2. Replacement ignition switches have a grey wire that is powered when ignition is off. It's not needed and is usually cut off when the switch is installed. Sounds like a likely culprit

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  3. May well be, possibly for parking lights through the indicator switch when the ignition's off (which Bays don't do).
     
    Bigherb likes this.
  4. Thought it was to power the 'you've left your lights on' warning' when ignition turned off..?

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    PanZer likes this.
  5. Possibly.
     
  6. I couldn't see the left your lights on buzzer in the wiring diagrams, what year did that start? According to this article it's never used though https://www.jbugs.com/VW-Tech-Article-Ignition-Switches.html

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  7. Ooo I need that!
    Been caught out a couple of times.
    Suppose if I drove it more i’ll get brainwashed in to remembering.


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  8. As Snotts said it for the indicator controlled parking lights required in certain countries.
     
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  9. mikedjames

    mikedjames Supporter

    If you have solar panels and LED side and tail lights, you can leave the lights on 24/7 ...
     
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  10. Thanks guys...

    Cable is live when all else is off so possibly not for the lights left on warning buzzer... though I am planning to fit one...

    The indicator controlled parking lights looks like the answer here...

    Though now it dawns on me... following the standard wiring for the stereo using constant live and an ignition live... I cant have the radio on without the ignition having to be on... No leisure battery at the moment...

    Hmmmm...
     
  11. If your ignition switch has been replaced with a more modern (eg Golf) one, you may have an additional "S" contact. This supplies +12V so long as the key is in the ignition switch (ignition off). Handy for a radio.

    Ign Switch:
    30 - +12V from battery
    50 - to starter solenoid
    15 - +12V supply, maintained when starting
    X - +12V supply, off when starting
    S - +12V when key in barrel
    P - +12V when ign off (parking lights, n/u)
     
    Last edited: Aug 23, 2020
  12. That's great...

    Thanks for the info... most useful...

    I did replace the ignition switch... but can't remember where it came from... JK, Heritage or the like... will maybe have to get under the dash again and hopefully it will have the terminal "S" you mention...
     
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  13. Does let you have the radio on without the current draw of having the ignition on. Very useful.
     
    DubCat likes this.
  14. Update...

    So... fiddling around with wires regarding radio and ignition... and consulting your link to Jbugs...

    The grey wire terminal “P” live when ign off, dead when ign on.

    The brown wire terminal “S” is ground wire when key in ign... open circuit when out... listed as “ignition buzzer”.

    Tested the “S” terminal at the switch to see if possible to route a supply through it but seems to use the body of the switch to ground.

    But... this leads me to thinking... maybe a relay could be fitted using the “S” brown wire to ground it so that when the key is in ignition relay closes and sends power to radio...

    Maybe thinking too much...
     
  15. Yeo, just use it as a switched earth, if that’s what it does.
     
  16. So...

    As discussed above.

    Fitted the radio using a relay via ignition switch to operate the non-constant live feed needed to operate the radio, alongside the constant feed needed to maintain the radio memories.

    This allows the radio to be powered when the key is in the barrel of the ignition without it needing to be turned on, and disconnects when the key is removed, so radio can't be left on accidentally.

    Using spare brown wire from the replacement ignition switch, which is ground when the key is in ignition and disconnected when key is out.

    After testing fitted the relay to the fuse board using tabbed spade connectors... relay came with bracket so could be fitted anywhere else convenient.

    Later/Replacement Ignition switch with six wires.

    Terminal No: and cable colour.

    30 - Battery Power from the Headlight Switch - Red

    15 - Power to the Fuse Box - Black

    50 - Power to the Starter - Black w/Red Stripe

    X- Power To the Headlight Switch - Black w/Yellow Stripe at Ignition Switch. Changes to Red w/Black at Headlight Switch harness

    P - Parking Position Power - Grey (live when ignition is off. Disconnects when ignition is turned on)

    S - Ground Wire for Ignition Buzzer - Brown (connects to ground when key placed in ignition)


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    Attached Files:

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  17. Is it the permanent live for the warming circuit in a Westfalia crumpet toaster?
     
  18. Just uncovered my ignition brown to try... doesnt earth on key .. grey gets live on key out but not much use for that... so looks like a permanently live radio for me!

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  19. Maybe try wiggling the key in the barrel whilst testing to see if contact can be made... if it does try a squirt of contact cleaner...

    Mine works but can cut out if I wiggle the key... new ignition loom but old barrel...
     

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