Q: Selecting a colour setting has no effect on my keyboard.When you run a program that uses your Mac's webcam, OS X will launch a background process called VDCAssistant, which manages the connection and control of the camera.

If no, then take your Mac to an Apple Store or authorized Apple Repair Center as it is a hardware problem. Here's one I found but you may be able to find others: Audio-Technica ATR2USB 3.5mm to USB Audio Adapter.