Electrical Problem / Battery Drain

Hi all,

I recently took my car in to Pepboys to get my alternator replaced because I had noticed that my lights dim sometimes during driving and after a long period of time the battery would lose its juice. Well, that and along other things like rear brake cylinder.

So, now it’s been 3 weeks and I’ve been having this problem where now it appears that the battery gets out of juice even more quickly. On top of that, sometimes while driving, both the brake and battery indicator light on the dash board would flash simultaneously for a split second. This becomes even more apparent and often when Pepboys replace my out of juice battery for free, though a lesser model because that was the one available at the time.

Now, after some testing in my presence, it is shown that there is some drain somewhere in the car that’s causing the alternator to not be able to charge the battery fully while driving – therefore causing it to go below the required voltage level to trigger the light on the dash. They attached a meter of some sort across both terminal of the battery with the connector to the car hooked on and off. While connectors are connected, the meter shows a drain. While the connectors are off, the meter is able to read the normal voltage across the terminals. The question, then, is where is this drain…

The fact that both the battery and the brake light comes on suggests to me that there’re some wires in the brake assembly that’s exposed to the bare metal of the body structure – therefore causing a short to trigger the brake light on the dash. I need to take this car to an electrical shop (though recommended by the service manager at Pepboys) nearby, and I’d like to hear some suggestions as to how to deal with this fix. I’ve already put too much cash into this car, so I’m looking for ways to reduce my repair bill by perhaps having the guys examine some likely areas for drainage.

Anyways, any suggestions would be greatly appreciated! I thank you in advance.

You did not mention Year, Make, Model, and Options. Such information is generally very important if you want accurate advise.

I’m suspecting you have a Honda or Toyota. The test circuit for the alternator light and the brake light on these cars are connected, so an alternator problem trips both lights. I’ve owned Toyota’s for a over 25 years, and the newer one’s are still connected like this.

Your having an alternator circuit problem, but no brake system problems. The fact that the drain has been checked and verified with the charging system means you need to see an automotive electrician to find the drain. This is important, because today’s cars are rolling computer systems, and those electronics do not respond well to electrical stresses. This could wind up costing you a lot more than the alternator.

Sorry for the newbie mistake. The car is a 2000 Mistubishi Mirage 4DR DE.

Oh, and thanks for the help.