I have a 0.5A battery drain on the BPM circuit (fuse 5 LH heelboard).
Have been hunting through the car and found zilch so far.

I was thinking that the rain might have triggered this so opened up all the door cards and checked if there was water in the connectors perhaps - no luck there though.

Does anyone have any ideas of how to approach this?

 

check the trunk and glove compartment lights. Feel them; if they are very hot, they have been on a long time.

 

Hi Jim,

Just tried those - disconnected the trunk bulbs and checked the draw with the glove box open too. Wasn't those from what I can ascertain.
Still doesn't add up. This will be a painful process!

Chris

 

Jim,

you've made me realise that I hadn't flipped the trunk lock whilst checking the fuses!
There in must lie the reason for the draw.

Whether or not I find the reason for why the battery was draining is another matter! Back to the drawing board :-)

Chris

 

Maybe; let's hope that's all it is.

Quick story: years ago, in Japan, I had a 10 year old BMW 2500 that was killing batteries right and left. I couldn't find the draw: a CPO who had repaired German cars part time while stationed in Germany, told me it was the trunk light: "It is staying on!" I put my 6 year old son in the trunk and told him to pound on trunk lid as soon as it got dark: "Don't be scared." No pounding came. How come: "didn't dark Daddy, the light stayed on. Ran the crate for five more years on the last 'BAHtry' I paid for.

 

I have now disconnected the trunk lights, just in case.
Got a feeling in my bones that this will be a Never Ending Story!

 

I had exactly this problem with a Series III! It just needed a bend to the metal tab that presses against a microswitch on that car.

 

It is a lot safer and more child friendly, to set the video on your phone then shut it in the boot/trunk or glovebox .


When you watch the playback it is obvious if the light goes out or not.

 

These modern cars always have a continious queescent electrical drain
even when completely shut off to power the main ECM and other functions.

 

Are you taking these readings just after shutting the car down?


It takes quite a while after the turn off of the ignition until the computers go into shut down mode.


They take their command to go into a timed shut down sequence from when the key is withdrawn from the barrel.
There is a little flap that covers where the key goes in, make sure it covers the hole when the key is removed.


I think it is somewhere on this forum the shut down times, if not try the JTIS or jagdocs.com.