If you are asking what the part number is for your Fakra, you shouldnt need it, you should bring to your dealer as they have left out a part that is included in your build. The FAKRA is part of the chassis harness. Get under the truck and look at the back bottom of the can on the drivers side for the wire coming out of the back wall through a D shaped small grommet. That is the body side cable pass through and should connect to the chassis side FAKRA with a white connector.
If you want to DIY instead of having it warranty fixed, here is a FAKRA sealed female to female Fakra:
https://a.co/d/9sXWcM8
You may need the male on one end so you can add this small jumper in that case:
https://a.co/d/9aYsuLa however, keep in mind that these cables are RG174, not RG58 like factory and may add some resistance which could cause performance issues. Also, if that plug was hanging out in the environment, it is likely corroded and will probably not work well either and you may want to attempt to re-terminate withe one of these
https://a.co/d/dsqFgQI if you are capable. Again, factory is RG58 and this guy may be too small for use on that wire.
Btw, your situation backing up difficulty would not be helped with this particular camera as it is
purely a horizontal viewing rear view style, not a typical backup camera viewing angle that points down so you can see your bumper and any obstacles to get around or back up to. What you will see out the mirror view will be about 20ft behind your trailer which is great for rearview mirrors driving forward but not for backing up. It does compress the full height of the camera view so you see a bit more down when you put it in reverse, but still useless for backing.