I have a 2006 TL 5AT and the battery light keeps coming on about 1 minute after the car is started. I have replaced the battery which was under warranty and have had the alternator checked twice and both times it turned out good. Anyone got any other idea why it might be coming on?

 

the wiring for your alternator may be lose or faulty, the reason the light comes on is that the alternator output isn't enough to keep the battery charged, so if you have a bad connection you'll have weak output.

 

That's exactly what was happening. The cable that cOmes from the alternator to the fuse box had a bad connection. I took it off, cleaned both areas and made sure the screw was tight. Problem solved.