One for the sparkys!

  1. Frequent Poster Joined: May 2010 North East Scotland Posts: 686 Inferno 182, S2 Indigo Rallye
    #1
    Right the permanent live wire for the radio had completely bunt out yesterday. The whole length from the multiplug to the radio loom the sheathing had melted off. What would have caused this? I have now spliced a wire off the permanent clock wire, (with an in line fuse!) and the radio still works, so it couldn't have been that shorted out!

    Any other ideas?
  2. Established Member Joined: Feb 2009 ★ West / North Yorkshire ★ Posts: 1653
    #2
    A short in the circuit or the headunit drawing too many amps. Check the fuse rating its probably been changed for a 30A
  3. Frequent Poster Joined: May 2010 North East Scotland Posts: 686 Inferno 182, S2 Indigo Rallye
    #3
    Quote:
    Originally Posted by outrage_uk View Post
    A short in the circuit or the headunit drawing too many amps. Check the fuse rating its probably been changed for a 30A
    What would cause it to short? Wire touching bare metal? No just replaced the fuse it runs from with a 20A as per the haynes manual.
  4. Established Member Joined: Feb 2009 ★ West / North Yorkshire ★ Posts: 1653
    #4
    Could be a short inside the headunit its self. Run a decent gauge wire direct from the battery with 15 amp fuse switched with a relay on ignition.
  5. Frequent Poster Joined: May 2010 North East Scotland Posts: 686 Inferno 182, S2 Indigo Rallye
    #5
    Quote:
    Originally Posted by outrage_uk View Post
    Could be a short inside the headunit its self. Run a decent gauge wire direct from the battery with 15 amp fuse switched with a relay on ignition.
    But surely the headunit itself wouldn't work? I have already sorted it as described in my first post.
  6. Established Member Joined: Feb 2009 ★ West / North Yorkshire ★ Posts: 1653
    #6
    I mean if you wanted to sort it 'properly' ie ignition live and separate feed and not off a live wire for the clock...

    It would only take a few seconds of dodgy electronics to melt a wire depending on how many amps it was using. Were you blasting music out at the time?
  7. Frequent Poster Joined: May 2010 North East Scotland Posts: 686 Inferno 182, S2 Indigo Rallye
    #7
    Ah right. Nah not blasting, just listening to a cd at normal levels.
  8. Established Member Joined: Mar 2010 Bradford Posts: 1490 '02 VTR, '92 106 XSI 16v
    #8
    If the insulation has melted off, I'd have thought the cable is overloaded?
    If you send too much ampage down a cable that cannot deal with it... the cable will heat up.

    allthough, if it was overloaded, the fuse should have blown ...surely?
    unless you have put in a 'wrong' higher sized fuse?
  9. L-plater Joined: Jun 2011 Posts: 76 2002 VTR
    #9
    The fuse rating is most probably wrong. The purpose of any fuse is to protect the cable on overload or short.
  10. Frequent Poster Joined: May 2010 North East Scotland Posts: 686 Inferno 182, S2 Indigo Rallye
    #10
    Quote:
    Originally Posted by DavidsVTR View Post
    If the insulation has melted off, I'd have thought the cable is overloaded?
    If you send too much ampage down a cable that cannot deal with it... the cable will heat up.

    allthough, if it was overloaded, the fuse should have blown ...surely?
    unless you have put in a 'wrong' higher sized fuse?
    Quote:
    Originally Posted by AzzNoble View Post
    The fuse rating is most probably wrong. The purpose of any fuse is to protect the cable on overload or short.
    As I said already, I replaced the fuse with a 20A one which was stated in the haynes manual! Thats why this is confusing the hell out of me!
  11. Established Member Joined: Feb 2009 ★ West / North Yorkshire ★ Posts: 1653
    #11
    Might have been a dodgy fuse. It wont take many amps to melt through old french wire. Id say 10A is pushing it. I wouldnt think your headunit draws more than 10 anyway. Test it with a multimeter - direct on the battery and see what readings you get, if its anything silly, you know where you problem is.