It could be the cable or the connector on the logic board.
In my experience, the most likely place the damage will occur is where the cable that combines Wi-Fi and the camera come together into a single connector or it will be the connector on the logic board itself. It's highly unlikely that the cable/connector at the iSight camera will become damaged unless repairs were done there previously.
Now, it's also entirely possible that your camera has failed (especially if Wi-Fi is still working.)
There are a few ways to diagnose this, but this involves using another cable and/or iSight camera. If you don't have these items handy or you're not willing to purchase them (or perform this type of task), it's probably best that you take it in for service.