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Old 02-07-2013, 06:04 PM
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540iman 540iman is offline
resident, old fart
Location: N.W. Indiana
Join Date: Sep 2008
Posts: 1,873
Mein Auto: 2002 540i sport
Check current draw at battery after 16 minutes (don't open or close doors or do anything to re-start sleep mode. By measuring the current drain now use your education to lead you to the problem rather than start at fuse #1 and go down the line. If current drain is 20 amps then it probably is the FSU. If the current drain is say 3 amps then the infamous fuse 56 comes into play. If not the FSU or fuse 56, then you might start going down the line. I think some have reported 150 mil draw when asleep. Evenh that would be "ok"

Also, you can't check the batteries internal impedance-resistance maybe. Don't go and get too fancy with electrical terms out of context! We don't measure battery impedance ever.

Just suggesting we apply a little more deduction based upon what draw is as measured AT THE BATTERY first and then decide which areas of the car are best suspects. Remove negative battery cable and insert ammeter there in series with cable and battery terminal.

PS. Why go to autozone to test your alternator. Just measure battery voltAge running and not. Also, instead of going to autozone just pull the damn FSU and see if your problem goes away. You'll know in under 6 hours in DVM not used or immediately if current drain is being measured. KISS

Last edited by 540iman; 02-07-2013 at 06:12 PM.
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