L322 Parasitic drain query

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muddy_v8

Member
Posts
22
Location
Headley Down, Hants
Right being a dumb ars here if I'm doing a parasitic drain test on my L322 obviously I need to leave it 16min until it "should" go to sleep. However the fuse box is in the glove box and the boot. Now if I leave the doors and tail gate open (so I can gains access to the fuses) will the BCM/ the car go to sleep or will it see their open and keep itself awake ?

How else would you pull the fuses without re waking the car. Short of shutting the wife in there for 16min (or longer ) and she pull s them (the fuses that is ) and I measure ?
 
You could fake the doors being shut by closing the latches with a screwdriver while the doors are open. Bonnet open is easy - just disconnect the bonnet switch. Not sure about the tailgate. Then with doors open, fold the seats down and crawl into the rear !!

EDIT: but shutting the wife into the car would have the benefit of testing the sound insulation?
 
Have you already checked the usual drain suspects like heater fan, bonnet switch, etc ?

You can also disable the interior protection:
Screen Shot 2017-02-02 at 21.03.29.png
 
Yep I have tried loads of stuff. It's had the FsR. A brand new 110ah Bosch battery. Had all the amp and info tainment disconnected. I have had groups of fuses taken out. Heated seats, blowers, Elec seats etc etc.

The only one time I got the BCM to shut down was when I took all the fuses in the boot at once and it shut off (gear selector lights go out) BUT.... if you take the out one by one it stays awake !!! Aaarrrgggh

If I don't get this sorted she can stay in there !!! Also I have one of those fuse current testers will try that also
 
But if the wife moved while the car went to sleep the alarm would go off, and your back to square one, dam these cars are a pain:(
You can disable the interior detection by pressing the key fob again after locking the car, I think it has to be within 10 seconds of arming it. I do it if I leave my dogs in it
 
As Brian said check the headlamp wash, that was draining mine. I ended up pulling the fuse out and has been fine ever since. Don't have headlamp wash but at least the car starts :)
 
My parasitic drain turned out to be the second clamp on the positive lead, it was only half a turn loose but was enough to cause the battery to drain overnight as the car kept waking up
 
Mines def not battery related what so ever how annoying that would have been to find.

I'm going out to test further today, last night i pulled loads of fuses;

All rear fuses except tail gate and RF (central locking aerial)

Front seat heating 12,52
Headlight Cleaning 28
Heated rear window 2, 79
Heated windscreen 34, 47
Light Module 4, 9
Outside Mirror, 11, 17, 24
Rear window wiper, washer 41, 80

Still after 30min the BCM stays awake! So today i will pull the infotainment fuses again and then test the drain with amp meter and the fuse buddy and see if this shows anything..... However i feel this is all pointing to the BCM module itself... :-(

Any other suggestions more than welcome

Thanks
 
if you get any results from pulling all those fuses, start putting them back in one by one. Have you changed anything recently or added a new stereo??
 
No nothing has been added to the car from what I can see. It's completely factory std.

The only way I could get the BCM module to down power was by pulling most of the fuses. Then it was measuring 0.02 amp which is perfdct. I then re inserted each one whilst measuring the and it constantly stayed on 0.02, occasionally it would wake up after inserting a fuse but after 16min would go back to 0.02....

So all bonnet switch now back on and all fuses inserted and it's dropping to 0.02 after 18-20min ???!
I am back to where I started this morning but It's shutting down correctly now. How is this even possible??

I have tried starting it etc locking un locking and it's going to sleep every time I don't understand how it's now not draining excess amps yet I am no different from when I started
 
have you moved the battery leads for any reason? So it is doing what its supposed to do?
did any of the fuse's look burnt or corroded?
is there any damp around the bcm? Under the carpet's.
 
have you moved the battery leads for any reason? So it is doing what its supposed to do?
did any of the fuse's look burnt or corroded?
is there any damp around the bcm? Under the carpet's.

I have a cut off switch on the negative because of the battery drain so i have just been doing my amp drain test from there. It seems that once you have pulled a certain amount of fuses out the BCM will finally shut down and work for a bit. Then after a few drives it stops working again unit you pull enough fuses out for it to stop the drain. Next thing i will pull the BCM out and check for damage/corrosion etc

Isnt there someone on here that repairs those units ?
 
daft question, do you have anything hanging from the mirror that could maybe keep the interior detector busy? Air freshener for example!
 
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