E38 causing hair to be pulled out.

[colinrmoulds]

Appears to be an e38 problem,yup battery drain but with a slight twist,when all toys work ok battery is perfect when left for 1 day or 2 weeks,but when,cd won`t turn on or radio has no volume or tv has no volume or navigation has no volume battery goes flat as a dodo overnight,as soon as you boost-pack start it all seem to work ok.Auto electrics looked at car for 4 hours could not find any fault at all, to say i`m lost for idea`s is an understatement.The car in question is 1999 740il,i love the car but this is causing just a bit of a headache to say the least,any help or ideas would be very very pleasing to hear,many regards Colin..

[Podmore]

There's obviously a parasitic drain somewhere. I have heard of the a/c final stage resistor causing such a problem .... to clarify, you are saying the battery seems OK for days or weeks but dies again AFTER the toys stop working? But can you start the car when the toys aren't working? I'm not clear on the order of events here ....

[Jearry]

I have the similar thing going on. I hadn't quite made the correlation of the 'Toys' stopping working. But about every ten days to two weeks, the MID for audio / cd controls will be blank when i start up first thing in the morning. I've found that if I'll shut the car off (98-750il) disconnect the neg battery cable for thirty seconds or so (Not long enough to lose seat memory) everything will work fine. If my wife gets in and just turns the sound system off, sure as anything the car will be dead by the weekend. I've had four Optima (Napa clone) batteries since 2002. Just about had enough of this car, except I love the way it runs! Maybe I could just learn to disconnect the battery weekly?