campermama you have to pair the cameras to the monitor. Not sure which monitor you have but there is a menu in the setup to pair. You select this choice and then the camera you want to pair then you need to press the monitor pairing button on the camera for 3 to 5 seconds. The camera will then pair and start to show a picture on the monitor. I just had a Vision S with a rear and 2 side cameras added to my trailer. The manual that came with it didn't say anything about pressing a button on the camera. If you go to Furrions website you can download a manual plus their technical support seems to be top notch so don't hesitate to send them an email or call. Good luck.