back up camera on factory nav display

Hello again, I'm having an issue with my back up camera on my factory nav display. I bought an aftermarket back up camera from amazon and bought a naviks video interface from eBay for my 1998 lexus gs400. All connections done for interface as required, and back up camera has good power and ground with properly connected rca's. When I put vehicle in reverse, my image is distorted/flickering I guess is the best way to put it. I can't get a solid picture. Any thoughts on this would be greatly appreciated. Thanks

a couple of possibilities, bad equipment. Insufficient voltage on camera, video pos and neg backwards. I am not familiar with that interface and since I don't know what camera or how either piece ties into the vehicle that is the best I can do. Break out the DMM and test voltage at camera using camera pos and neg to be sure you are seeing the same as the camera. to check if it is video pos neg you will need to flip flop those wires.

Figured out issue. I had two wires backwards. Camera works fine now. Thanks for the input!