We purchased a 2003 Tundra new in 2003 and had to buy a third replacement battery today - the first replacement battery was about 2 years ago and the second was earlier this year. The problem seems to be worse when the weather is cold and it was -10 this morning. The battery intermittently goes dead - sometimes when it's not driven for more than 2 days. We turn off the fan, lights and radio/cd player and it still goes dead. We don't use any accessories that plug into the cigarette lighter. The only thing we could see that is still on when we shut everything off is the blinking anti-theft light but understand that it's supposed to and it's just a low power consumption LED light. After paying $167 after discount with taxes this morning, we'd like to have an idea what the problem could be before bringing it to the shop. Any ideas out there?