The locking on its own thing is a bad microswitch. And they probably can drain your battery. If you search around, there are links on the problem. Its a common failure. I just don't have the links handy right now.
After I read your post I had this happen to me while driving on freeway it died and had nothing left and the alternator drained my battery good.So,in the end it was bad alternator. Went to Autozone,bought new one with pulley. About $190 with taxes. Called friend of mine who actually works as car mechanic,replaced alternator in about 25-30 minutes. Didn't look really that complicated as I tought. I forgot to mention that I have 1999 GL 2.0, 99750 miles,batik blue. Also,interesting that in moment when alt died somehow bulbs in both headlights did burn,so I had to replace them also. Paid $20 for both bulbs. So now everything works fine, I am back on the road. Next thing to fix is gonna be that door latch. Thank you all..