[Q] Moto G brightness really dim topic

My Moto g brightness is really dimmed to the point I can not see the screen. First I thought it was the screen display. So I brought a new one but i'm still having the same problem. Then I took everything apart and I'm left with the motherboard, battery and the screen. When i plug them two things in the motherboard and turn on the phone and put it near a lightbulb, I can see the screen. I'm wondering how I can fix this problem. Please help.