My 2003 sedan will not start. . . again. I replaced the battery for a 3rd time (at dealer's suggestion) 3 months ago. I've also replaced the circuit board twice. When I came back from a 10 day vacation, my car wouldn't start. When I turned the key, I got no lights at all on the dash. The car was completely dead. It required a jump to start. This is a repeated problem, and has happened to me before after the car hasn't been used for a few days. Any suggestions?

 

It could be that all of your charging system is peachy. Your problem may be excessing drain from a problem with the security system or a short circuit from a grounding fault. Measure the current/drain from your battery when the car is off. Compare that to a G that is functioning properly. That should start you off in the right direction. Then you can start pulling fuses with the car off to figure out when the drain stops- then follow the wires...

 

^^
It sounds like a parasitic drain, as he said above. If it were a poor alternator, you should be seeing the alternator ("battery") light coming on.

 

+1 - was thinking your alternator is bad too...if its bad, it won't be able to charge the battery properly.