2003 TL3.2: parked outside for about 2 hrs; won't start when came back; keyless did not work; meter lights and exterior lights did not work; radio & power window did not working... BUT, step light on the door and inside reading light are working fine (no sign of dim).

Jump start works fine: all power operations work; radio requires code. Cannot start itself after 30-min driving. Jump start still works. Connectors on battery is dirty though, but does not look like it's a connecton issue.

Looks like I have a dead battery, but I am confused: why the interior lights work perfectly well. Can anyone give me a quick answer? And a link about how to do battery change is appreciated.

(I'm out of town and cannot work on the car right now.)

 

take it to the nearest auto parts store, most do a test for free. it could be the alternator too, but sounds like bad battery.

 

Battery. Make sure the connections are clean and tight. The little lights work because they require so little voltage. A auto parts store can load test your battery and tell you for sure. Many battery places will replace the battery for free if you purchase from them. If you want to do it yourself, disconnect the battery cables, loosen the 2 bolts that hold it down and remove. Reverse for install.

 

it sounds like your battery is dead.. but just to make sure
get a voltimeter and measure the battery voltage while the car is running. the voltage should be around 13 to 14. this means that the alternator is charging. if you still get 11 to 12 volts this means the alternator is dead..
well basically its either the battery or the alternator
good luck!!