Weird lighting problem

Discussion in 'Tech/Mech General' started by tuglet, Apr 2, 2016.

  1. tuglet

    tuglet

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    Hi all, after some advice from the experienced electricians. On our 2012 plate Rollerteam TLine 700 on a fiat Ducato we have this unusual external lighting issue. When I turn lights on all external lights illuminate then after about 5 seconds the following lights go off. Rear left, Rear upper right led marker, rear left hand side Amber marker strip and front left side light bulb. When I brake rear left brake works perfectly. Whether lights on or off. On the internet I read a suggestion from other people's questions that Fiat Ducato monitors light circuits and will de-energise a circuit if it detects something slightly strange on any lighting circuit, sometimes accompanied by a dash lighting warning. I don't get any dash warning lights. Others have cleared lighting faults by disconnecting both batteries, presumably to reenergise the ECU which is controlling the lighting circuits. I have tried this with no success. Embarrassed to say I was an aircraft electrician to trade in the past but without wiring diagrams I am completely foxed by our issue. Anyone any ideas - all help gratefully accepted. TIA.
     
  2. gus-lopez

    gus-lopez Funster

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    Hi & welcome. Sounds a bit like an earth fault to me.
     
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  3. scotjimland

    scotjimland Funster Life Member

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    agree with gus-lopez

    most lighting faults , especially weird ones, are bad earth connections , rusty , corroded or broken .. or water in the lamp holder

    marker lights are favourite .. remove and inspect, starting at the top front
     
  4. andy63

    andy63 Funster

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    It does sound classic earth fault,but the fact that they all come on and work normally for a short period may mean it's a electronic control fault... If a detectable fault was causing that you would expect a warning light to come on...
    That's my thoughts... but hope you get it sorted and let us know what it was....
    Andy
     
  5. Badknee

    Badknee Funster

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    Could be a heat build up earthing problem? When the bulb heats up the earth breaks down.
     
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  6. Lenny HB

    Lenny HB Funster

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    Sounds like an earth problem but your van has a canbus system so could be another electrical fault that is nothing to do with the lighting circuits.
     
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  7. TheBig1

    TheBig1 Funster Life Member

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    this is actually pretty common but can be hard to fault find. the side light circuit is drawing too much current so the ecu protects the circuit by turning off.
    bad connection on front side light
    bad connection on connector under the cab by the loom extension joint
    bad connection at marker lights
    bad connection on rear light cluster
    a bulb starting to fail so high resstance
    a bad earth at any of the affected lights

    sometimes you find it first time sometimes it takes hours
     
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  8. tuglet

    tuglet

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    Thanks all for some sound advice, i will try changing other filaments one at a time - already changed out rear left as this was the first we noticed. Need to get van out of driveway to work on it so probably next weekend. Will post if I find a solution.
     
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  9. tuglet

    tuglet

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    OK folks the knowledgeable amongst you were right. When I managed to investigate the problem this morning the side lower position(?) light was the culprit. The filament holder within the unit was full of water and there was the obvious short. Guess the body computer was detecting the short and deenergising that circuit of lights for safety. All cleaned up dried out WD40 applied all reassembled and lighting problem solved. At least I know for next time. Phew one happy Moho owner again and roll on last week in April when we head down to Cornwall for a week!!
     
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