I got a 2003 Mustang this year, and for the most part it works awesome. The only thing is that it seems that the electric's are all jacked up. Sometimes my dome light doesn't want to turn off, and then sometimes my windows won't go down. My window wouldn't go down for like three months, and then all of a sudden it started to go down again. I am pretty frustrated. Any advice.

 

check the electric fuse box

 

The items mentioned are controlled by a single module called the GEM (Generic Electronic Module) I would check for switch and fuse issues first, but the gem is the brain, some call it a body control module.