Cadillac Repair: 1999 Cadillac, jumper box, cigar lighter

Question
Every once in a while like today my wife went to start her car.  It was completely dead. Nothing worked, she called AAA.  The battery was fine so he attached a jumper box and asked her to try an start the car.  The dash lights came on but it would crank the starter.  She turned it off and tried again then it started.  The same thing has happened before.  Any idea what is the issue?

Answer
Hello,

By nature, we all know the battery is key element in power supply for the vehicle. The battery is only one part of a much larger electrical system.

Now, there are numerous possibilities as to what is wrong and without being physically present at the vehicle, I cannot help you. However, the first thing I would check for is a parasitic draw. Very easy to do. Remove the positive battery cable. Put one end of a test light on the cable and the other end on the positive post. If light comes on you have a draw. Go to the fuse box (extra one in trunk)and pull out a fuse. If the test light does not go out. Re-install and go to the next and on and on until you find the fuse that will shut the test light off. Then you know what circuit the problem is in.

Common sources for draw are ant, cigar lighter, dome lites etc.

If test light never came on showing a draw, I would take a volt meter across the battery to see if it is charging. It should be around 14.2 volts. If not, you need an alternator.

If any of this helped, please rate my answer. Thanks,

Rob