We have a Furrion Vision S wireless camera and monitor that we use with our Forest River camper. The camper came pre-wired and with the Furrion mount, so the camera made a lot of sense to us. Our experience with the Furrion was exceptional UNTIL we upgraded our truck from a 2016 Silverado to a 2021 GMC Sierra. When we did this, the camera stopped working.
I tried everything: checked all the wires; removed the camera to re-sync; added a wired antenna to behind the cab - no luck. I even bought another Furrion Vision set to see if that would work - no dice.
Turns out the new GMC and Chevrolets have a new power setup that runs less power/cycles to the running lights and make most wireless setups (not just Furrion) useless. You can buy a $100 workaround (that is not available until October - thanks COVID) that MAY fix the problem, or you can swap to the new GM system that mates up with the tow vehicle's infotainment system ($$$$$!).
GM is well aware of the issue - so is Furrion. So far, no certain fix is in the works.