One in a million electrical faults

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  • redface
    redface Forum Participant Posts: 1,701
    1000 Comments
    edited July 2016 #32

    Ah Snowy - if only I had known of you when my wife's car was misfiring and not even Nissan, the manufacturer, could say which pot it was. The misfire was sporadic but their computer could not read the fault codes.

  • Snowy1
    Snowy1 Forum Participant Posts: 263
    edited July 2016 #33

    Ah Snowy - if only I had known of you when my wife's car was misfiring and not even Nissan, the manufacturer, could say which pot it was. The misfire was sporadic but their computer could not read the fault codes.

    If it was me, I would of try'ed using an Oscilloscope, sure it would of shown up, I am by no means superman, it's just I will not give up until I find the fault. The answer to a vehicle electrical fault is always within the vehicle it's self.

  • Snowy1
    Snowy1 Forum Participant Posts: 263
    edited July 2016 #34

    Many moons ago when i was in the road transport section at work i had a lighting fault on an artic tractor unit.All was ok until we tried the brake lights and then it was like strobe lighting all over the vehicle.After a coupe of hours the fault was traced
    to a brake light bulb.The bulb was a stop/tail bulb and the stop element had broken and fallen across the side light element
    Sad joining both circuits together which causes all sorts of problems.

    v9

    Those symtons were common when a customer put a single filament 21w bulb in stop/tail socket .

    Yes Martin, I agree that a bubble or even a single contact 12v/21w bulb will fit into a 21/5w bulb holder even though the 21/5w pins are offset, all one has to do is push said 12/21 slightly deeper into the holder and it will fit as you say.

    Colin

  • EmilysDad
    EmilysDad Forum Participant Posts: 8,973
    1000 Comments
    edited July 2016 #35

     ....Those symtons were common when a customer put a single filament 21w bulb in stop/tail socket .

    My car does actually use a 21w single filament bulb as a stop/tail Wink

  • Snowy1
    Snowy1 Forum Participant Posts: 263
    edited July 2016 #36

     ....Those symtons were common when a customer put a single filament 21w bulb in stop/tail socket .

    My car does actually use a 21w single filament bulb as a stop/tail Wink

    Yes some cars do, the system is known as; Common feed wire method, shared control wire method or shared filament lighting Method. Said 12v/21w bulb is feed by a single wire, when the sidelights are switched on the towcars ECU feeds a voltage of around 5v to the bulb. This allows the bulb to partially light up giving equivelant lux of a 12v/5w bulb, therefor acting as a sidelight. When the stop lights are applied full 12v is feed to said bulb and the lux is of corse equivelant to standard 12v/21w bulb. This system catches out unskilled towbar fitters who try to wire towbar electrics without using a correct module, I.e. They cannot electrically separate the two circuits back into two to correctly wire the towbar up.

    Colin

  • Snowy1
    Snowy1 Forum Participant Posts: 263
    edited July 2016 #37

    Sorry, PS again,

    Some cars have this method between the vehicles' sidelights and rear fog lights. 

  • Snowy1
    Snowy1 Forum Participant Posts: 263
    edited July 2016 #38

     This system catches out unskilled towbar fitters who try to wire towbar electrics without using a correct module, i.e. They cannot electrically separate the two circuits back into two to correctly wire the towbar up.

    The above is true, but there is actually a way of fiddling this by connecting the modules' stoplight signal wire directly to the towcars' high-line LED stoplight and the modules' L + R sidelight signal wires to the towcars licence plate lamps. In my opinion, I would never of done this to a customers car as in my eyes, it would be a Bodgit & Scarper job that would be OK for a Local Scotch-Lock Mob. One should always obtain the correct module for the towcar every time!