2010 Carolla 51,000 mile, car was dead,charged battery, pass air bag light on.

The battery is a brand new Toyo just installed beginning of month. The alt has been checked it's good. The only thing changed in car was the factory radio was bad. I know it shouldn't matter that the dealership replaced. But something has to be draining batt. There r no other lights on checked, just that air bag pass light blinking as some as key is removed. Any ideas?

Do you know if pass air bag light, located by clock should be blinking on and off every second. Not sure. Car was fine, is at dealership being they sold to me as is. Had in writing that they would stand behind car