VGER,
Thank you for your inquiry. Furuno USA does not recommend cutting and splicing the antenna cable and as such does not offer a "splice box" for this purpose. Although we are aware that 3rd party manufacturers may have this product available, we do not recommend a splice as done improperly damage may occur
That being said the best method is to fold the flat 9 pin cable connect back against the cabling itself and use electrical tape to secure. Then run the cable UP from the display towards the radar antenna.
As its a factory made connection removing to 9pin connector is not recommended, however in certain situations where the diameter of the available wire run makes pashing the cable through the wire chase, it may be the only option available to you.