2004 e83 X3 battery drain, fuse #49

[sayemthree]

I have a battery drain I checked it and pulled all of the fuses until I found it was fuse 49. something will not let the brain go to sleep. every few minutes it drops from .32 amps to almost zero them wakes up again to .32 amps.. when I pull this fuse the battery doesn't drain.

fuse 49 controls the
central locking
front windows
alarm ( don't think I have one)
interior lights
windshield washer

all lights inside go off after a few minutes. any ideas where to start and how to check individual components?

[Matt at Pelican Parts]

Hi sayemthree,

I would investigate into the possibility you have a module that is not going to sleep causing a drain on the rest of your system. On many European or modern vehicles it usually stems from an electrical chassis component such as the radio, amplifier, bluetooth module or other electronic box.

I have seen on a Z4 around the same year where the bluetooth module was not going to sleep and was constantly looking for a signal causing the battery to drain.

On BMW's, you also have something called an LKM (light control module). This box controls much of the functions of your internal and external lighting systems. They also can sometimes be the cause of a battery drain and may be worth investigating.

With a standard generic scan-tool you may be unable to diagnose some of these components. You may need something more powerful with the ability to read the CAN-Bus system like our BMW/MINI Schwaben scan tool:
https://www.pelicanparts.com/More_Info/PEL014020SCH01A.htm?pn=PEL-014020SCH01A