I recently purchased this vehicle from an auction. I took it home and replaced the spark plugs on it. Before replacing the plugs it ran a little rough. It smoothed out afterward. Then I started having problems with it not cranking. The lights and gauges on the instrumnet panel would lite up and the car would crank. After changing the plugs sometimes the lights on the panel do not light up and the vehicle just turns over. After awhile if you just bump the starter and wait the gauges will light up and the car will start and then all of the sudden, it turns off by itself as if you turned the key off. My local GM dealer performed a diagnostic and told me that the batery was to weak to get a reading so we replaced the battery and that seemed to cure the problem for about a week and now it is doing the same thing again. Any ideas? The lights that i am talking about are the regular dash lights that show you the guages and shows that you have power to the dash not the check engine lights
Problem with car not cranking and then turning off on 1999 Cadillac Seville SLS
by buck264 in Boerne, TX on January 17, 2010
ANSWER by dandd , January 17, 2010
Try charging your battery and then starting your car and then make sure that you have 14 volts at the battery terminals, if not, your Alternator is not doing its job. This is a good place to start.