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How can I track down a short / parasitic drain?

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OK, getting to the bottom of my hard to start problem I think.


Seems that the battery is caput - but why, its only 2 years old - "well thats batteries" I hear you cry.

Yup, I accept that and I am going to replace it BUT

I thought I would do a few checks.


Disconnected negative and placed my multimeter across the gap - between 1.4 and 0.8 amp drain with everything apparently 'off' = PARASITIC DRAIN apparently.

Checked the alternator - not that.

Disconnected each fuse in turn - not that [not just the fuse box ones aswell]

Disconnected each relay in turn - not that

Disconnected the ICE - not that

Disconnected the clock - you guessed it - not that.


So what then? Of the 4 connections to the positive battery terminal, only removing one removed the drain - the group of heavy wires - brown, brown, brown/red


So, I next went to the ignition switch. Not sure why right now, but my circuit diagram reading took me there. Seems the live brown wire (direct from the pos terminal I think) has a weak but definite earth connection.


Sooooo, I think that means that somewhere in that wire (or one of the others in the group I guess) there must be a short to earth - correct or not?


If correct, is there any clever way to track it down or is it, as I suspect, a case of tediously tracing of the wires through everything and everywhere?


Also, can anyone explain why when I test the parasitic drain, as explained above, there is an initial 1.4Amp drain which then settles down to a steady 0.8 after, say 2-3 seconds. Something 'waking up' and then 'going back to sleep?'


All this makes me sound like I know what I'm doing - far from it. Just working logically. please feel free to correct me if I have made an error in my assessments somewhere.

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How about interior light as it gives full power then dims may be door switches jumping???? sorry but having a glass of whiskey after a nice meal in the local.

andy b

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OK, I'll check that.


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I ended up fitting a battery master switch. Turn the thing OFF and there's no chance of a current drain....

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Appreciating I'm in a different generation of Esprit, but I had exactly the same level of parasitic drain from the starter motor assembly.


According to the auto sparky who eventually repaired it, the solenoid can fill full or wonderfully conductive residue from a life of hard duty and is enough to allow some juice to flow but not enough to do anything more.


True to his word, disconnecting the starter saw all my parasitic drain vanish.

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