We have owned this Mustang since 2008. It is a 2006 and has 27,000 miles. About twice a year it will drain the battery overnight. What makes it hard is when you put in a new battery or if your lucky and can save the old one, I may not have a problem for another 6 months. At one point I looked out into the garage to see a very dim glow. The backup lights were on but not brightly. I removed the lights and charged the battery but several months later it drained it again. It was under warranty at one point but the dealer could not find a problem. They said the next time it does it we will bring it in on a rollback. Problem is once you install a new battery it resets whatever is wrong and it has no issue for months. So again they can't find a problem. I'm on about battery 5 or 6 and the car can't be trusted. Car is clean, low miles, sits inside. Any good ideas. I don't care if it takes some parts or money to fix it as the car is not intended to be traded or gotten rid of. I just need to get it fixed. It appear it may be a long time to fix because no matter what I do it will be months before I'll ever know if it is fixed. Maybe all year and maybe tomorrow morning.