Electrical problems

[nvterp]

I have a 2008 Aveo, was in Los Angeles on vacation and the brake and battery light came on. It only came on when taking off from the traffic light, at highway speeds it was off. Was hoping it would get home to Utah. Heading home the light was on from Rancho Cucamonga to Barstow. Stopped in Barstow and had the guy at O'reilly's check the electrical system. They said battery and alternator tested good. The battery was bowed out, he suggested buying new battery. So bought a new battery and went on my way. Brake and Battery light off all the way to Vegas. As soon as we get on city streets lights come on again. Next morning no lights at freeway speeds lights on city streets. We get home ok, next morning car battery dead. Charge battery and take it to sears (only place open on Sunday) they said everything tested ok but there is a drain on the battery when car off, I believe he said 4 volts/amps. Take it to the family mechanic but he can't find what is causing the drain on the battery. Take it to the Chevy dealer and he says that the alternator is over-charging and I need new alternator. They wanted $840 for parts/labor. My mechanic $309, so he puts in new alternator, But now the brake and battery light are on all the time but really dim. Mechanic not sure why so going to take to dealer again. When I got home noticed that the headlights are now acting up. Daytime driving lights - driver's side on passenger side off. Headlights turned on - driver's side off passenger side on. Turn to brights - both sides working. Any clues to what might be going on? Thanks!

[avguy]

Well, the good news is you now have a new battery and alternator. The bad news, it sounds like neither one needed to be replaced.
Did your mechanic at least zero in on the circuit causing the problem? That's normally just a matter of pulling fuses, until the culprit is found. It may then be more difficult to find the exact cause (broken/stripped wire, ...), but at least it gets you into the right ballpark. It sounds like the light circuit is the primary suspect, but if the '08 uses the same old infamous splicer, that would be another possibility as well.
I hope you can find a shop that can do this work right (i.e. find the battery drain), without hanging any more unnecessary parts (skip the stealership that sold you the alternator). This is another classic case showing why some of us try to DIY whenever possible.