the backlight of lIPHONE 4 with cracked acts funny

[mostafa_mostafa]

I bought an iPhone 4 with cracked screen to fix it. After I went back home with the phone I started to notice that the backlight goes on and off by itself all the time. The phone didn't and doesn't have service so far. The screen is completely cracked and some pieces are falling apart from the screen. Also sometimes it display the same alert as when you try to shut it off although the battery is fully charged. Please help