All right, so even though it's not a Mazda, maybe I can get some help here. My 07 Cobalt has been in my possession for nearly 6 years. Never really any problems...until recently. So back when I bought the car, I installed an MTX ThunderLink sub/amp setup (100 watts, all in one type deal). In 2011 I upgraded the head unit and speakers all around along with putting in aftermarket projectors and HID's. Sometime last summer I swapped out the MTX for a Kenwood amp that puts out 460 watts and the Boston G5 sub. Not too long after doing that, I had an issue...driver's side HID burnt out. Less than a week later, passenger side burnt out. Took out the HID's and put in H7 bulbs (SilverStar Ultra's). Swapped back to the MTX after a few months due to selling the Kenwood/Boston setup. Now, I went with a lower wattage amp (200w) and a Polk sub. Installed it all on Thursday morning...Thursday night...driver's side headlight went out. I'm sure it can't be coincidence. Any ideas? First time it happened I thought maybe moisture got in or something else...didn't really think about the extra draw from the amp. Now that it's happened again...I'm guessing it's not moisture. Could it be my wiring? The ground possibly? The alternator itself? I've heard of overcharging, but never experienced it. Coincidence? What? I'll get the alternator checked out...and the battery (if the problem is the alternator since the battery is only a year old). I'll also double check all my wiring and probably re-do some of it. I can't afford to be replacing headlights often so I need to get this figured out sooner than later. Last question, if it is the alternator, would you pay ~$150 for a reman? or should I take a chance and spend $30-35 at John's or A-Abco? I know A-Abco has used for $30 that are tested with lifetime warranty. Thanks.