I read a post on the Thor forum where a member (Oldgold) had added a 9" monitor to his dash and tied in to his camera system, two other members made the same mod and I decided to follow in their footsteps. I hated the factory Axerra system, I had to lean over to see it and the screen picture quality is very poor.
I purchased a 9" monitor from Rear View Safety, https://www.rearviewsafety.com
which I received quickly, nice people. The installation was fairly quick and easy to do. When I ordered my monitor I also chose to use a Ram mount rather than drill in to my dash.
On the dash I already had a suction cup disk and attached the Ram mount to that. I cut a small notch in the forward corner of the removable dash cover to run the wiring harness. If you have the little silver switch box for your factory camera system installation is a breeze. The monitor comes with a harness that connects directly the the factory camera plugs, just unscrew them from the box one at a time and connect to the new harness. The switch box also has a connector which has all the other wiring you need, power, ground, and trigger wires for reverse and turn signals. After cutting and splicing in the wiring I buttoned up the dash and was done except for calibrating the monitor.
Monitor calibration was fairly simple, contrast, brightness, and saturation (color). All three camera can be displayed at the same time in several different configurations to suit what you prefer.
Toatal installation time was about 30 min and IMHO very worth actually being able to see my video display.