BMW 540i elctrical fault that is draining the battery when standing?

This problem started a couple of weeks ago and is baffling the technicians - any idea's

BMW 540i elctrical fault that is draining the battery when standing?nortin

Hi, disconnect the battery earth lead(the black one).

Then put the black lead of a multimeter on the battery and the red on the lead you have disconnected. make sure the ignition is `off.

Set the meter to amps and read the screen - it will say how much drain is being pulled by the faulty source.

The reading should be less than 0.5 of an Amp preferbly.

If it is not less than that proceed to remove fuses one at a time until the drain drops below 0.5 Amps.

When it drops you will then know what circuit is causing the drain by what number fuse you have removed - check the manuel for fuse listing.

When you know what circuit the problem is down to you can then check that circuit individually.

The usual fault is an interior lamp left on in the boot or a dodgy alarm system in either case it is easier to leave the fuse out as long as it does not supply anything else...or you could of cause rectify the fault.

BMW 540i elctrical fault that is draining the battery when standing?pc security

A friend had the same problem on his 850 and I'm sure he said it was to do with the air conditioning, can't remember what exactly.
follow nvr stop jmmn and you'll be on the right track. this is how we track down our draws.
alternation, is the boot light on. has it got an a alarm try not using it.