Re: 430 RBZ Upgrade to 430 RHB (Nav)
When the dealer added the sales code for the RBZ to your order, this gets associated within your vehicle's VIN equipment sheet in the Chrysler system. Basically it looks like you ordered the RBZ and camera from the factory.
Coding the camera to function with your RBZ unit was a separate action the dealer would need to have taken and has nothing to do with warranty. My understanding is that there is a menu where you can activate and de-activate the rear camera on the 430 models. If your dealer doesn't code/activate the camera, you will not be able to select the camera from this menu and hence it won't work.
Here is my suggestion, get and install the new head unit. Check to see if the camera functions and if the camera menu is operable. What I found is most used head units HAD rear view cameras previously so the fuction was already coded. If it's not, the dealer should be able to recode the camera for a nominal shop time charge (1/2 hour?). In addition, you can ask the dealer to swap your RBZ for RHB on your sales order to get the new equiptment covered by warranty.