HELP battery drains in 3 nights and transfailsafe whenever replacing new battery

[B318RV]

hello guys...
i have this problems on my E38 M73N 750iL AT 5HP30
I often leave my car in my garage for at least 3 nights and most of all a week due to traveling abroad often...
so my problems are...
my battery runs out and drop to 10v when i leave it in my garage for 3 nights.. and never warm up
anyone know where this problem source might be?
i already tried to disconnect the interior lamp fuse... still the same...
then the thing i do is to unplug the battery pole whenever i traveling abroad...
and then a new problems start to kicks in...
a trans fail safe prog appear in my dash everytime i reconnect the pole battery and start the engine
and my tranny stuck on 4th gear i think...
when this occurs... cant be scanned by the gt1 or isis...
and the thing i have to do is to unplug the EGS connector whih located under the plastic box under hood and infront of my 2 DMEs...
then after 5secs i plug in back the egs connector... and everything went well and runs smooth and great...
untill i disconnect the battery pole again...

then recently i bought new battery (its amaron dry cell)
and still the same
my alternator reads 14.17v on the battery when idling...
i think its no problem...
also recently i do try to jusy disconnect the small positive cable which lead to a black fuse box located near the battery in the trunk...
and my trans fail safe prog reapear....
so i think... it somehow from the box or the harness...
please do anyone tell me what that black fuse box is for...
and if anyone have the wiring diagrams,... it will be better,,,

please help me

[Timm]

More info here:

http://www.meeknet.co.uk/E38/E38_Battery_Drain.htm

Wiring diagrams here:

http://www.bmw-planet.com/diagrams/release/en/

[rdorman]

Ammeter between cable and negative post. Pull and replace fuses until parasitic draw drops. That circuit is your problem.

[B318RV]

More info here:

http://www.meeknet.co.uk/E38/E38_Battery_Drain.htm

Wiring diagrams here:

http://www.bmw-planet.com/diagrams/release/en/

Thanks a lot... thats very helpfull.... will be back report soon on monday..
With pics if possible and result...



Ammeter between cable and negative post. Pull and replace fuses until parasitic draw drops. That circuit is your problem.

Ok sir... thanks a lot... will back with the report soon


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[serious7series]

the nav is draining your batt when you leave the car unlocked. I discovered the same exact problem with my 750. solution: buy a brand new BMW aux battery (~$250) and buy a trickle/float charger (battery tender is perfect). Plug it in whenever youre not driving the car.

[xboss]

Not the greatest solution though. The drain should not exist.

[B318RV]

the nav is draining your batt when you leave the car unlocked. I discovered the same exact problem with my 750. solution: buy a brand new BMW aux battery (~$250) and buy a trickle/float charger (battery tender is perfect). Plug it in whenever youre not driving the car.

thanks anyway for the quick solution...
and what brand is ur charger ?
may i have a hints....


Not the greatest solution though. The drain should not exist.

yes indeed...
i agree.. the drain should not exist...
mine solved before... its the ihka thing...
but now the problem comes back after 2 years

[serious7series]

Brand: Battery tender plus. BMW uses the same one, but slaps a BMW logo on it. And raises the price of course.

[B318RV]

ive tried all the tips above...
and bad news...
still reading 1.5mA on my meter...
will try to test it again after finishing my work on the harnesses...
becos my +pole harness is breakin apart... hehehe

[B318RV]

Great news... finally i hoped... foud a lot of interior and audio system's wiring are "nude" and might cause short inside when grounded...
And here are some pics i add...
Now my ampere meter read 0.45mA hope my battery will last 70 days...
Still leaving 1 problem... my engine failsafe now on... instead of my transfailsafe...
Anyone know where i need to start?
I use ultrascan to scan... and it reads relay fuel pump... idle is vwry steady and smooth... just feel a delay and gap on acceleration pedal... please do help... what might got wrong

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[B318RV]

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