Camera wifi and light

On your phone I'm not seeing any common connection between those three parts. The camera is connected directly to the motherboard via a flex cable and the flash is soldered directly on the motherboard, so there isn't anything like a bad flex cable going on here.

You'll definitely want to try and figure out if it's a software issue first. Try rebooting the phone and if that doesn't help, boot into safe mode. To get there, hold down the power button until the Safe Mode prompt appears. Tap that button and the phone will reboot into safe mode.

If the issues are still present in safe mode, that tends to indicate a hardware error. In this case there's nothing external to replace, so my best guess is you'd have to replace the motherboard to fix this. You could try just replacing the camera as there's a small possibility an issue with that could also affect the flash, but I don't have a high degree of confidence that'll help. On the other hand, a camera will be cheaper than a motherboard, but you'll have to make that decision yourself.

Good luck, and be sure to come back and let us know how it all turns out. What you learn will help the next person who comes along with the same problem.