2020 Anthem Rear suspension air pressure gauge.

I have a 2020 Anthem i recently purchased. It didn't have the air pressure gauge for the axels in the menu. I was "told" by the dealer i bought it from (i didnt notice it didnt have it when i picked it up)it has the sensor on the right rear airbag and that it just needs to be turned on in the menu.
I took it to my local dealer, who first daid no, it doesn't work like that. But then they had it for another reason (DEF LEVEL SENSOR) they put a new sensor on the rear airbag, turned it on in the dash, but it won't read it. The tech wrote that he installed and accessory kit? And he can see the pressure in the bendix program but it won't show up on the dash. They charged me $400 for that, darlings that they are.... so, does anybody have any ideas? Have a friend with the samebyr truck and he has another sensor on his front left airbag that I dont have and his gauge works?
Thanks!