Woke up to a dead battery: E46

[drz]

Background: Drove in from work last night with no issues at all. Nothing out of the ordinary. About four weeks ago, the idle control valve was replaced. All doors were closed, key was not in the ignition, lights were off.

Problem: all electrical pretty much dead. Can't get the engine to turn over. I haven't tried push-starting, but I don't think I am going to with the battery in this state.

I'll try to get the battery checked out, but I doubt it would just go out overnight like this.

Is there anything you know regarding the idle control valve install that could affect the electrical?

Suggestions as to what to check?

[witeshark]

This exact situation happened on a friend's mom's Cadillac Catera; it turned out to be a faulty rear de-fog relay.

[drz]

Thanks wite. I don't think I have the time to debug this. I will probably have to bite the bullet and take it to the shop if the basic checkouts don't yield any results.

[dpzacek]

idle control valve hums when engine is off. even when key is out of the ignition. any idea where to start checking? 1990 525i.