Q: car wont start and battery light on on 1999 Mercury Sable

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
car turns over slowly than just clicks. i tested battery with multi meter and battery tested good.
(1) Answer
A multimeter is not a good enough test for a battery. A battery with standing voltage of 12.6 might show good, but as soon as a load is put on it, if it drops below 10.5, it's no good.

Your battery light -- is it on while the vehicle runs? If you can't start it, then your battery light will stay on with your other warning lights with the engine off. If you can start it with a jump and the battery light stays on - then you have a charging system failure - alternator, voltage regulator, wiring connector...

Hope this helps.