battery warning light, low headlight output, then trans failsafe = alternator?

[John Galt]

Is this problem likely the alternator?

Is it best to replace the whole thing, or can I just replace the regulator? In other words, is it common for just the regulator to fail, or is it normally something else in the alternator?

E53 3.0i

So, I'm driving home from work today and the battery warning light was on the dash.

Then I noticed that the headlights seemed a bit dim.

Then I got a bunch of other warning lights.

Then the trans fail safe came on.

I managed to get home, but the car would not turn over after I turned it off. Dead battery symptoms when I tried to start it again.

The battery is maybe one year old.

I have not had any recent electrical or starting related issues.

The car has 200k miles.

I'll try to jump start it and check out the running voltage tomorrow.