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electrical wiring burnt out

Discussion in 'Fuel System & Electrics' started by madmaddy, Mar 20, 2010.

  1. madmaddy

    madmaddy Member

    Messages:
    68
    Location:
    Sydney
    Head lights are working now after fiddling around, I think t was a bad earth.
    Now have a bigger problem, reversed kombi out today to give a wash, started washing away when I noticed smoke coming out of the dash everywhere. Opened the doors and the smell was electrical, in a big panic quickly disconnected the earth at the battery, then the smoke cleared. Looked under dash and at the head light switch wiring and the wire that feeds the interior lights has melted completely thru and has travelled back to the middle interior light, the front one is ok. Does anyone know why this happened? I think I will take it to a auto electrician as I don't completely understand it.
    Thanks Jen
     
  2. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,905
    Location:
    Penna, Hobart
    With the way you have described it, you have at least a short in the interior light. That is the only way you will burn that wire. possibly a water leak nearby the light? current flows down the wire to the switch on the light then to the globe then to the earth. If the wire has melted at the light end then there must be a short to the body there. If no burning at the light end then the short is somewhere between the switch and the light, in the body, and the water from washing has lowered the resistance and the wire has turned into a heater element and melted the wire, probably not quite enough current being drawn to melt the fuse wire. Long story short, where the wire has stopped melting is where the short will be.

    May seem a little complex but that is what is causing that part of the problem.

    Adrian
     
  3. madmaddy

    madmaddy Member

    Messages:
    68
    Location:
    Sydney
    Thanks Adrian. We had another thought as to why this has happened. The rear interior light was reinstalled recently and I thought that maybe whilst washing the roof with (broom on stick) the roof may have flexed down in this area and metal may have touched terminals on the light fitting??
    What do you think? I have photos so will try to attach them.

    Cheers
    Jen
     

    Attached Files:

    Last edited: Mar 22, 2010
  4. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,905
    Location:
    Penna, Hobart
    That would be a likely start but wouldn't have thought it would have done that much damage. According to the original wiring diagram that light is fed from the fuse S8 and doesn't go through or from any relays, like you seem to have. If it was connected this way it would have blown the fuse before that amount of damage occurred. I am just wondering why it was connected that way in the first place, could have been from the PO. Have you got a better pic of the relay and the connections?

    Adrian
     
  5. madmaddy

    madmaddy Member

    Messages:
    68
    Location:
    Sydney
    Yes we probably should connect the wire to the fuse box. Is there anyway I can email the photos to you direct? I'm having to crop them heaps to get them on here and they turn out too distorted :p

    Jen
     
  6. Van Housing

    Van Housing Well-Known Member

    Messages:
    10,432
    Location:
    Yarraville Vic
    Hey Jen, you don't have to shrink or crop the pics if you use a photo sharing site such as photobucket (rather than attaching the pics). You open a free account with say photobucket.com, then upload the pics to there. You then copy the "" tag from next to/under the picture, and paste that into your post. There are more details here, good luck: :)
    [url]http://forums.kombiclub.com/showthread.php?t=11446[/url]
     
  7. madmaddy

    madmaddy Member

    Messages:
    68
    Location:
    Sydney
    Thanks For that I will give it a go. Cheers Jen
     
  8. madmaddy

    madmaddy Member

    Messages:
    68
    Location:
    Sydney
  9. madmaddy

    madmaddy Member

    Messages:
    68
    Location:
    Sydney
    YAY I did it!!!

    [​IMG]
    [​IMG]
     
  10. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,905
    Location:
    Penna, Hobart
    Ill look forward to them. If you take the fuse box off you should be able to see where the connections to the fuses are. Disconnect the battery first and then remove the 2 phillips head screws on either side and then carefully pull the box out a little so you can see over the top past the relays. There are spade terminals there that you can connect to . if you take the fuse for S8 out then check either set of corresponding terminals, with the battery reconnected and the ignition on, for voltage and connect it to the spade terminal on the not live side.

    On the same fuse terminal should be a red wire that goes to the hazard flasher switch . The wire from the fuse to the interior light should be black and then connected to a red to go to the rear light(standard bus with 2 interior lights). From the front light should be a brown white wire that goes to the door switch if fitted and from the rear light a brown one to the sliding door switch. From the other side terminal there should be a red wire to the ignition switch and another that goes to the headlamp control switch (not the dipper relay).

    The info is from a gregory's manual which is a good starting point as it has the electrical system laid out in a closeish approximation of the location of most components. You can find it at the local library along with some others.

    Cheers

    Adrian
     
  11. madmaddy

    madmaddy Member

    Messages:
    68
    Location:
    Sydney
    Ok cheers, I'm onto it :)
     
  12. t4camper

    t4camper Active Member

    Messages:
    330
    Location:
    rainy Maleny
    You are quite lucky that the wire burnt through just beyond the light switch and did not ignite anything else.
    You did the right thing to disconnect the battery.
    From the photos it would appear that the postive wire from the headlamp switch melted through at the break point. Small bead of copper on each end of the wire, that stopped the short circuit.

    Adrain picked it correctly, the fault had been at the centre light. I can not determine if it is on the spade lug or on the wire nearby.The remains of the plastic near the spade lug may indicate that the original short circuit was just above the bulb.

    Water is not conductive enough to initiate or propagate a short in 12 volt wiring.

    Definately a requirement for a fuse at the start of that circuit. That gauge of wire should be protected by no larger than a 10 amp fuse.

    Both wires that run from near the light switch up the pillar and across the roof will need replacing, the brown with white trace, from near the light switch to the door switch should be ok to cut and join into.
    Check to see if the old wire is free to move when pulled from either end, if so, join on a new twin cable and pull new cable in as the old one is pulled out.
    Strip plastic off both conductors of new and old wire for about 5cm. Pass strand over each other and twist back along themselves. Put some plastic tape over your joint. Try and keep the joint smooth as possible. Whilst feeding the new cable in, guide it out with the old wire. Take time and work gently, feeding down hill has gravity assist.
    If the old wire is stuck, you could try to use a cane to poke a new wire in, electricians use the plastic tongue from the chip board flooring joining strip. Usually found on building sites for free.
    Neil
     
  13. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,905
    Location:
    Penna, Hobart
    Thanks for the better pics. Nasty mess. The red wire from next to the interior light wire I take it is the power feed wire, and that should be the other cable from the ignition switched S8 fuse. If is not fused or has a 15 amp or larger fuse that is probably the reason why it burnt up with out blowing. The light wire would be lucky to be 10 amp wire, more likely 8 amp. once you have sorted it all out change it to a 8 amp fuse and give it a go.

    Adrian
     
  14. madmaddy

    madmaddy Member

    Messages:
    68
    Location:
    Sydney
    Yes we have found that the interior light wiring was ONLY wired to the Head light switch and not a fuse. The previous owner had attempted to turn the bus into a camper, he had disconnected the rear light and mounted a 240v light there. We decided to remove it and could see the existing wiring underneath so bought a new light and wella new interior light and it all worked! We really should have seen if it was connected to the fuse. Fuse S8 has a wire coming out of it but when we pulled on it it popped out from up under the dash it was short and had a plastic vw plug on the end of it and not attached to anything. We just wanted to be certain of what the cause of this was. We have also since found that the wiring loom that's runs along the roof where the two lights are joined had a lot of green stuff on the copper wiring that was left after melting.
    Also where the rear light goes into roof recess the spade terminals must nearly touch the metal roof, I measured the gap then measured the light fitting and there would be lucky to be 1mm clearance, could have the positive spade shorted on the roof. I just want to know why this happened when it did, because the light has been in for about 3 months.
    Anyway next job is to run new wires and start again thru the correct fuse.

    Jen
     
  15. saabman

    saabman Well-Known Member

    Messages:
    4,862
    Location:
    Goulburn
    Id recomend using insulated spade plugs on the light connections to.
     

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