05 TL Battery or Alternator?
 

I have been riding my motorcycle the last few weeks and noticed that when I started my TL recently it barely started, yesterday morning it didnt. I tested the battery and its a at 12.56v. I had a charger on it last night and it still didnt start this AM. If I jump it with my truck it runs fine until I turn it off. Im thinking the alternator is toast and of course its right out of warranty (05 w/46k). Any ideas or should I go thru the steps of new battery, then alternator?
Maybe call the dealer and whine? :)
TX
Dan

Alternator won't cause the battery to go dead when the engine is off. The battery is weak and won't hold a charge, or there is a parasitic drain. Take the battery to a local auto store and have it checked.

Is it an original battery?

Yes it is the original battery, I put a Optima red top that I had laying around and charged it and it starts but seems like the Alt is keeoing it running and once the battery drains again it wont start again.

sounds like u have a drain somewhere...try charging the batt then leaving it disconnected from the car overnight. if it starts in the morning its a drain, if not its a battery issue...