Backlight Functional - LCD Not Functional (Help Please)

The screen on my iPhone 4 was cracked so I decided I would replace it with a new one. I am not new to repairing iPhones as I have been doing it for a lot of my friends recently. But on this one after I replaced the screen with an a complete front assembly, and when i tried turning it back on only the backlight would work. However, there was no image. I disassembled it and checked the wires for faults, and there were none. Once again, only the backlight worked. Would it be the part because it could possibly be faulty? Could I have messed something up on the motherboard to cause this? I would like to have some advice/help ASAP. Thank you!

Also, the phone is recognized whenever it is connected to a computer. The only thing that does not work is the display on the phone.