One light, left on 24/7 in your car can kill a battery.
Sometimes we forget to turn things off
Yes, I have to admit it. I did not know that, when I bumped my head against the back seat's vanity light while taking out the wheel chair unintentionally clicked on the light switch and left it glowing for several days before our car's battery was drained and nearly dead.
This exact thing happened over a year ago with the same battery. And it happened to be the driver side door vanity light. But finding out it actually was this tiny light bulb left on for days that did the job of almost destroying a perfectly good battery.
My friend and I were at a loss as to the cause. First he connected the battery to a charger, then he reconnected the posts, after doing a cleaning of the terminals and wire connectors. We drove around for a few days not having any troubles at all, but it wasn't until a few days later that , once again, the battery had gone down to just at 10.1 volts. Not even a click with the remote clicker, not even a light from the dashboard. It was stone dead, again.
While charging up the battery once more and having applied spray to the terminals with a special protective coating I got into the fuse box in the trunk and we began checking each fuse one by one until he suddenly realized that the sparks on the battery were being generated by the charger itself. I lost the fuse puller. We went up to buy another one. Then we kind of figured the battery was just plain no good. But after taking it up to Auto Zone, the man told us the battery was in good condition. That made me think I would have to pay a lot to have a mechanic run a diagnostic on the entire electrical system.
But as we sat and discussed the matter over the local news and ate pizza, the sun began to set. My friend told me we could get a new battery or have the car's system checked the next day with a multi-meter, and as he walked down the steps, smoking his cigar, he turned around and looked into the rear window of our car. "Hey Anthony", he said, "There's a light still on in the car." I looked and there was the cause. During the day it was not apparent as the sun's glare on the windows of the car made it hard to notice, but in the dark of night, that tiny vanity light was shining bright. After all I remembered banging my head against the door frame a few days back.
I reached inside and clicked on the light and it turned off. The vanity light was the cause of this but it was a lesson well learned, not a day wasted. Hind sight is in fact, for me this one instance, 20/20.
Several days passed and the battery never went down and maintained a normal range around 13.4 volts.
Yes, indeed. I saw the light!