Battery draining....
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Grrrmachine
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You're on the right lines checking for parasitic drain. Trouble is that if none of the fuses are responsible then it must be hard-wired in, meaning it's either an alarm or a stereo. A Clifford alarm should have its own fuse somewhere though.
'89 325i Touring | Touring Resto Thread | In-Dash Screen install
- Brianmoooore
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Not everything electrical goes through the fusebox. You need to separate the smaller red wires from the battery + terminal and use your meter, still connected in series with the negative lead (I hope!) to determine which wire the parasitic drain is disappearing down - one of the two or three red wires, or the thick black one.
4.36 what, BTW?
4.36 what, BTW?
- Brianmoooore
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4.36A should kill the battery in a day! There should also be a fair bit of heat generated where it's going as well.
I suspect you'll find the current is going down the big black wire.
I suspect you'll find the current is going down the big black wire.
- Brianmoooore
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Starter motor (unlikely suspect) and alternator.
- Brianmoooore
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One of the red wires goes to the fusebox. Thick black wire goes first to the starter motor solenoid, then changes to a thinner red wire, which goes on to the alternator.
Sounds very much like one of the diodes in the alternator has gone short circuit. Confirm by disconnecting the red wire from the alternator, connecting everything back up, and then checking the drain again. Something like 0.06A is fine.
Your alternator is not readily repairable, so you'll need a replacement. Check the condition of the carbon brushes on the regulator pack on the replacement, compare them with the ones you have now, and use the one with the longest.
Sounds very much like one of the diodes in the alternator has gone short circuit. Confirm by disconnecting the red wire from the alternator, connecting everything back up, and then checking the drain again. Something like 0.06A is fine.
Your alternator is not readily repairable, so you'll need a replacement. Check the condition of the carbon brushes on the regulator pack on the replacement, compare them with the ones you have now, and use the one with the longest.
- Brianmoooore
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Diodes aren't part of the regulator pack, unfortunately. Part #7 here: http://bmwfans.info/parts/catalog/E30/T ... parts_90a/
- Brianmoooore
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Whatever was wrong with your car, a corroded fusible link did not cause a battery drain!811 wrote:i had the same problem a few years back, eventually took it to an auto electrician.. he replaced a corroded fusible link in the boot near the battery & all was well.
- Brianmoooore
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If your old alternator and the 'recon'. one are the same make and rating, and you have a heavy duty soldering iron, you could try swapping the diode plate over.
ok, but never had the problem again after he replaced it.. so i assumed he was right!Brianmoooore wrote:Whatever was wrong with your car, a corroded fusible link did not cause a battery drain!811 wrote:i had the same problem a few years back, eventually took it to an auto electrician.. he replaced a corroded fusible link in the boot near the battery & all was well.
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Grrrmachine
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Yeah, stop being a fairy and test the alternator!
'89 325i Touring | Touring Resto Thread | In-Dash Screen install
- Brianmoooore
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Jumping needles could well be the SI board batteries starting to die as a result of a flat main battery.
- Johnaldridge101
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I have a very similar problem, only just bought the car but eager to get her sorted for when and if the weather gets any better, having a standard alarm and a Clifford I thought they could be the culprit, I will start pulling wires and investigating.


