Turn signals only work with dome light

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by richgoff, Sep 28, 2020.

  1. richgoff

    richgoff Bobtail Member

    21
    5
    Jan 28, 2010
    richville NY
    0
    i have a 2012 T800 with a ISX.
    The turn signals only work with the dome light on.
    Flashers work fine on their own, all the market lights and head/ tail lights work with the dome off.
    I replaced the module on the steering colum, i have a good ground there.
    When i put a test light on the wires, i have power all the time on all the wires coming out of the module, with the dome on and off.
    I have a good ground at the light.
    I'm beating my head against the wall with this thing, if i knew where to jump a wire, i would!
    Any help would be appreciated
     
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  3. stillwurkin

    stillwurkin Road Train Member

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    Dec 2, 2017
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    Can you pop out breakers or fuses to make dome light go out? Sounds like the fuse block could have corrosion? Mayby moisture getting in? I know from experience that could be it. Once my cab marker lights would come on by themselves, had water in the breaker. Windshield was leaking at the edge. But just have to keep looking around. Maybe block dome light off and leave it on when running. Something will turn up, if no one has a solution. When you shut down to rest or leave truck very long i would cut power to dome light, at the least. Things could get hot. Probably not . Just to be safe.
     
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