no power to my 1985 520i bmw (auto) when lights on

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bernabmw520i - 14 Apr 2004 07:28 GMT

I lose power in my 1985 520i bmw when the head lights are on... What is
causing this? I heard it may have something to do with the brake lining -
this light comes on occassionally when the lights are turned on - I have
no power with the headlights on though

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psycho@here.there - 20 Apr 2004 22:54 GMT

>I lose power in my 1985 520i bmw when the head lights are on... What is
>causing this? I heard it may have something to do with the brake lining -
>this light comes on occassionally when the lights are turned on - I have
>no power with the headlights on though

This is pretty vague but I am assuming you lose all electrical
power when you turn on the lights. Sounds as though you have a short
circuit in the headlight circuit that is killing the car. If turning
the headlights on kills the car (and I'm willing to bet the lights
don't light either) then that is the problem. A short this large would
seem to do more than just lose power though. Do you smell anything
burning? Does turning the lights right back off cause everything else
to come back on? What's the condition of the battery?

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Dave Plowman - 21 Apr 2004 10:03 GMT

> I lose power in my 1985 520i bmw when the head lights are on... What is
> causing this? I heard it may have something to do with the brake lining -
> this light comes on occassionally when the lights are turned on - I have
> no power with the headlights on though

First thing I'd check is the fusible link fitted to the battery positive
lead - these are known to give trouble. Connect a voltmeter (DVM) across
the input and output of this - if it reads zero with the lights off, but
12 with them on, that's your problem.

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Dave Plowman dave.sound@argonet.co.uk London SW 12
RIP Acorn

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