So while I was on deployment my car battery died and my wife had it changed out. It is unclear if the MMI quit working before or after the new battery, but I have tried almost everything to figure it out. When you turn the car on, the screen is black and the buttons on the control module do not light up. I have checked every fuse in the car and I even removed the Amplifier and unscrewed it to see if the curcuit board was damaged and it was all in good condition. I do not have access to a scanner to run diagnostics and I do not have the money to take the car to the shop.