mysterious battery drain?
 

I recently had to purchase a new battery and I'm experiencing a overnight drain. (the old one was just bad) I remember when I first got the car, leaving the cellphone connected would pull on the battery overnight. But I haven't had the phone connected in months. I had my alternator tested and found out it was faulty. It's been replaced. I don't drive this one every day, but may twice a week. Anyone know what else could be draining a perfectly new battery leaving the car a few days in the garage?

thanks

The phone module is certainly one possible culprit. Also check that when the car has gone to sleep that the fan in the climate control unit is no longer running. Leave the boot lid open, close the latch manually, and check that the 2 lights go out after 16 mins, and that the nav 'on' light has gone out too

When you say leave the boot lid open, what does this mean? Also what two lights do i need to check for? The navigation "on" light. Does that mean the LCD display?

Sorry, but want to try your advice immediately. Not sure what else would pull on the battery overnight.

He means LEAVE THE BOOT OPEN but trigger the lock so the body computer THINKS IT IS CLOSED. Wait 16 mins (or there abouts) and check the COURTESY LIGHTS in the boot have gone out. If that tests good test for actual battery drain current and start to disconnect permanently connected items until the drain stops.

Check the light next to the shift level, if is going out after 10-15 min. after you park the car Check the operation of the windows, interior lights, sunshade lights,alarm, central locking,windshield wipers, as they might indicate a culprit in the GM III (general module). Also navigation, radio issues?
Also do you have a correct battery replacement?
A nice DIY for battery drain: http://meeknet.co.uk/E38/E38_Battery_Drain.htm
or: http://meeknet.co.uk/E38/BMW_E38_Ele...l_Gremlins.htm
Credit to Tim for his nice website: http://meeknet.co.uk/E38/Index.htm:thumbup:

Some other reference:
http://www.bimmerfest.com/forums/sho...=battery+drain
http://www.bimmerfest.com/forums/sho...=battery+drain
http://www.bimmerfest.com/forums/sho...=battery+drain
http://www.bimmerfest.com/forums/sho...=battery+drain

BOOT & bonnet are the Euro English words for "trunk" & "hood"....just as lift = elevator & *** = cigarette. Some of the other former or remaining British colonies may use those terms as well.

The "nav" unit is in the trunk and has a (I believe) red LED that illuminates when the unit is on...check to make sure that the LED on the nav unit itself (not the car's monitor in the dash) turns off when the car goes to sleep. It takes 16 minutes for the car to go into sleep mode. If you activate a door handle, window, or push any of the buttons on the remote...you will "WAKE" the car up...extending the time for the car to go to sleep.

As mentioned above, the little light next to the gear shift is another indicator as to when the car has gone into SLEEP mode.

Awesome instructions. Now this spells it out for me nicely! I will be trying this in the morning.

thanks!

Sorry - didn't realise the hood/bonnet - trunk/boot thing. You US chaps should learn the Queen's English...................

Will try mate! :bow:

:):thumbup:

Nice to remind our US chums of the origins of their language sometimes....:):)