You can test which camera is not working by using other Apps to start facetime cam. The app crashes and shows black even if only one cam is not working. But I guess it´s only the one on the back. Try this first because it's quite easier to replace than the front cam. If you still got camera issues replace the Facetime cam. This should solve your Problem. These guides will help you to perform the repair.
iPad 4 Wi-Fi Rückkamera austauschen
iPad 4 Wi-Fi Frontkamera Austausch
You´re quite lucky that you own the wifi version, which makes the replacement quite easier than iPad with cellular.
And don´t use any sharp or metal tools when removing the touch screen this will damage the color coating.
War diese Antwort hilfreich?