If the grid lines are displayed when you put it in reverse then it's the camera, which sounds like it was originally the issue. As sh30469 stated, there is a TSB on the camera itself because they get water in them and KIA will pay to replace. I've had mine replaced once and the second time I ended up taking the camera and blowing it out with compressed air which resolved the issue. Now I'm having issues with the display going out completely when in reverse (no grid lines) which Cadenza preferred customer service said was the AVN, which is only covered up to 36,000 miles. It will stop working for a day then come back on so I haven't taken it to the dealer for replacement under the extended warranty.