battery keeps draining overnite, new battery what could be draining my battery?

Make sure ALL lights inside are turning off with doors shut!!... **Especially the 'rear' dome light!**... best done at night... IF no luck, have mechanic do a parasitic load test!

it could be many things but lets start with the Dome lights, Door lights, Engine lights, Trunk lights. Clock will also drain your battery. I found a light was on in my trunk because the switch would not shut off the power when i close the trunk so i had to repair the switch. Also you can unscrewed all the lights that you can see and see if that makes any change. it also could be a bad cell in your battery or your alt. is not charging back into the bat. one more thing if you have a alarm on your auto then that can be the problem also. take it back to auto zone and have them put in on there comp. and see what code it gives. also check your bat. and see if the cables don't have a short.