Why did my car's battery "die", and then work again?

I own a 1996 Ford Escort LX station wagon, in very good condition and well-maintained. Anyways, I headed to my car after work today, and proceeded to start the engine. For half a second, everything seemed to work normally, but then almost immediately, the automatic seat belts stopped moving and the car wouldn’t start anymore. Repeated attempts at starting the engine were unsuccessful. Great, I thought. Here comes a huge repair bill. I started to think about what the problem was, and then realized that none of the lights worked. I thought perhaps the battery had simply died, even though there was no prior indication of this, and I had a new battery put into my car in February 2003.

Anyways, I got out of my car and opened up the hood. I looked at the battery, and it seemed normal. I lifted up those little rubber coverings on the two terminals to see if anything was visibly wrong, but nothing seemed amiss. I couldn’t see anything else wrong with the motor. I climbed back into my car and then, incredibly, the car started immediately, with no problems.

So… apparently it was the battery, but what could’ve caused it to basically not function? And why did everything work again, even though all I did was lift up the rubber terminal coverings? Was it perhaps just a bit dust and grime that was in the wrong place at the wrong time? Static electricity buildup which then discharged? Cosmic interference? :eek: Do you think I should take my car to the mechanics’ to get it checked out anyways?

Most likely it was a loose and/or corroded terminal or cable clamp. Go to an auto parts shop and pick up a battery terminal brush. Remove each clamp and thorougly clean both the post and the inside of the clamp, and seat the clamp firmly back on the post and tighten well.

I’m extremely unsophisticated when it comes to cars. What are the clamps? Is that those metallic joints on top of the battery where the wires meet up? Is it safe to remove these? Do I need any special tools? Could I get shocked? Thanks for helping out a car newbie. :wink:

The clamps are exactly what you suspect. It’s safe to remove them as long as you’re careful. Just use an adjustable wrench, loosen the black cable first (or the one marked “negative” or “-”) and carefully set it to the side, then repeat the process with the other clamp. To clean them, any stiff wire brush will do, but a battery terminal brush will only run you a couple of bucks. Reverse the removal process to reinstall the cables. Yes, you can get shocked, but only if you’re careless. As long as the wrench doesn’t touch both terminals at the same time, you should be fine.

You should also pick up either a Haynes or Chilton manual for your car. It’ll show you how to remove the clamps (yes, it has pictures) and will help you figure out what’s going wrong whenever you have a problem with the car in the future.

It’s not particularly difficult or unsafe to do (it’s only 12 volts), but if you feel unsure about it, you’re probably better off going to a service station and asking to have it done. They probably won’t charge much, if anything. If you do decide to take a shot at it, all you need is a screwdriver and the aforementioned brush. The terminal clamps are held on with a screw, located under that rubber boot you mentioned. You just loosen this screw and twist the clamp back and forth until it works loose. then use the brush and remove any scale, dirt or corrosion until the metal on both the terminal post and the clamp on the wire is nice and shiny. Then, push the clamp back down on the post and tighten the screw to “hand tight”. Do the same with the other terminal.

Some terminal clamps are held on with a nut. You’ll want a flathead screwdriver anyway for prying.