Something keeps draining my battery!

[Se7en]

Hey i drive a 98 328is, and there's a problem with my car. Something keeps draining my battery! It takes a while for it to drain the whole battery, but overnight is usually when my battery gets drained and dies.

The battery is still good, i got it checked with a mechanic and he says it holds the charge just fine and it's a problem with my car.

There's no visible lights on when all doors are closed and off. Something interesting though, my cigarette lighter still outputs power even with the car off.

I'm not sure if this is the problem, or what it can be, but has anyone had this problem?

Thanks in advance.

[Dr. Flyview]

I think all our cig lighters have power with the car off... Check to see that the glovebox light and trunk light are off with the glovebox and trunklid closed respectively, although HOW you check I am not too sure on hehe.

[Se7en]

Believe it or not i checked both lol. I just turned on the video recording feature on my phone and both lights turn off when they're closed.

[97328ICGTA]

It happened to my Mercedes c320 too. Battery ran out overnight. It turns out the both of the driver side and passenger side memory seat modules failed.