Parasitic Battery Drain e53

[Fifty150hs]

Originally Posted by Bmwe5320023.0

Findings

Drops in parasitic draw

Drop from 700 mA to 430 - 470 when fuse 43 (Instrument panel) is pulled

Drop from 700 mA to 390 - 410 when fuse 48 (Heater/air conditioning (AC)) is pulled

Drop from 700 mA to 375 - 385 when fuse 27 (Multifunction control module 1) is pulled

Pulling fuse 14 (Multifunction control module 1) causes alarm to go off for some reason

While I was pulling all these fuses, I noticed something weird. Draw would sometimes drop to 300-400 mA or sometimes to even around 70-100 mA.
Then I noticed a faint sound of a fan. I knew right away it was the small fan in the heater control panel.
But while I was checking fuses, the fan would come on some times, and go off at others, within 1 minute. The draw would vary based on this.

Pulling fuses 27 and 48 made the small fan stop spinning and draw drops from 700mA to 400.

While sitting in the car I also noticed that the draw would randomly drop from 700mA to around 440 even with the fan spinning. So this must be the drop from the system going to sleep from fuse 43.

I did notice at some point when the fan stopped spinning, the small light on gear shift selector was off. And when it started spinning, the light was on.

So then I sat in a car for a bit and the fan stopped spinning and the light on the gear selector went off, draw dropped to about 70-100mA.

What's interesting, I definitely didn't sit for 16 minutes. So I'm not sure why the car goes to sleep so fast. And maybe it wakes up randomly for some reason too.

Then I noticed if I moved around in the car, the fan would come on and the draw would be back to 700mA.
Maybe it's the movement sensor in the headliner that activates this fan?

Then I literally stopped moving and within 1 minute the fan stopped and draw was back to 70-100 mA.
I then waved my arms in the car and then the fan activated and draw was back to 700 mA.
I repeated this sequence 3 more times.

If I move in the car, fan activates, gear shift selector light comes on and draw goes from under 100 mA to 700 mA.
If I don't move for 1 minute, the fan turns off, draw drops and gearshift selector light goes out.

I guess I'll have to do some more monitoring to see if the car goes to sleep or not.

If it does, I need to think it there's any other draw I need to find or if 70-100 mA is acceptable (I think it is).

The last step would be to figure out the camera draw. Plugging/unplugging the camera makes the draw go up/down by 200-300 mA. Not sure it the camera goes to sleep mode as well and the draw drops as well.

Motion sensor for the security system signaling the car to wake up when you move? I don't know, just a swag. Is car asleep when you are checking these draws? Takes about 15 minutes for it to go to sleep. The fan your hearing is in the IHKA and it draws air into the temp sensor for the heating/cooling system.