In order to add the grid lines to your Voyager RV Backup Camera w/ Night Vision - Rear Mount # VGR84VR you are going to need to get into the menu screen on your monitor like # VO34FR, and through the settings you'll just need to toggle the marker lines ON/OFF.
You can find more information on page 6 of the owner's manual, or you can check out the attached image. view full answer...