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      02-27-2013, 06:38 PM   #6

Drives: 2008 328xi
Join Date: Feb 2013
Location: Boston, MA

iTrader: (0)

I just spent 45 minutes in the car with the doors locked, glove box switched taped closed and a multimeter to hunt down the 12V non switched no sleep fuse locations. See the picture below (this is my fuse box), the red arrows point to the fuse locations (and I found an empty location) that are 12V constant/battery power (non switched, no sleep, blah blah). These fuses correspond to fuses: 2 (empty location), 3, 4, 54, 55, 72, 73, 74, and 75 on the 08 e90 fuse box diagram seen here:

A cool thing to note is that just by measuring voltage I could tell what mode the car was in. Key in the ignition not started the fuse box voltage was 11.98V, car locked pre sleep mode the voltage was 12.32V, and finally while the car was in deep sleep mode the voltage was 12.55V. This makes sense as the more current being pulled from the battery, the lower the battery output voltage (at the fuse box) will be because of internal resistance and wire resistance to the fuse box.

Georgia Tech Graduate, BS in Electrical Engineering

Last edited by gte460z; 02-27-2013 at 06:48 PM.