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2003 E46 320d - Battery Drain

4K views 10 replies 6 participants last post by  rusty520i 
#1 ·
Firstly I apoligise for starting a new thread on this, but most appear to have found the problem.
So I have a parasitic drain of 0.5A.
I have pulled all fuses, all the relays I can find and the FSR which is a common fault. Still have the drain.

Anyone ideas where I go next, short of checking the entire wiring system. A friend mentioned the Alternator diodes can play up and cause a draw but not easy to get to.

Please help!
 
#8 ·
Used to do this a lot. Diodes are pretty boring things. If you can the diode pack apart you can just replace them with something vaguely equivalent (if all else fails, the same size will have to do). You have to consider this a bodge - it might bugger the thing altogether or may make no difference (you need to be able to solder properly too). A windings breakdown (to earth) could have a similar affect too.

There are people about who recondition alternators. Might be worth asking for advice.
 
#7 ·
I might have the same problem: I have a parasitic drain of 0.4A
Yesterday I disconnected one by one all the fuses (in the glove box, are there any other left?) and the drain was still there
Somehow it wasn't completely stable 0.4A - it varied form 0.35 to 0.4 very slowly

So I guess I have to think about disconnecting the alternator and starter. Is it a difficult job?, haven't tried locating them yet....
 
#9 ·
Fixxed baby

Problem finally solved a month or so back. Got looking into it properly, found the lead I took off the alternator was the supply to the pre heat unit. Took said lead out off car altogether now no drain woo hoo! Running without preheat but shouldn't be a problem, I'm reliably informed its not really needed.:thumbsup
 
#11 ·
e46 2001 with 198500 miles running great but sudden battery drain overnight. After a few days, different battery, all fuses pulled but still 1.7amp drain. Eventually touched the electric auxilliary heater in engine bay next to the engine bay fuses and it was warm/hot! Disconnected and now solved battery drain problem. Hope this helps somebody.
 
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