So yesterday my '03 TL completely died after i parked it and turned it off. The interior lost complete power i.e. no power locks, no trunk latch, no dashboard lights, no emergency lights, etc. The only electrical component that works is the lights on the door. I've been reading around and usually the symptoms of a bad ignition were that the car would die randomly, which mine hasn't done that. I checked the battery (it was at full charge), fuses (none were popped), and checked the voltage from the battery to the switch and it was receiving 9 volts. I may be making a redundant question here, but I just would prefer to have the input of others as well just in case it can be something else.

 

9V would indicate a bad battery. Should be 12v.

Have you tried a jumpstart from another vehicle?

Check the voltage at the battery. If it's less than 12v, yank it out and have it tested at your local auto parts place. Most all of them do the test for free.