A few updates... As you may know, the 2019 HD rams moved the security module. This module has to be defeated in order to use devices like the AEV Procal, or Tazer RAM modules. In previous trucks (2018's) it was behind the radio, and in the 2019's, it moved to behind the gauge cluster. Not wanting to pull apart my dash (they seem to always rattle after that), and wanting a better solution, I used the KaodTech Security bypass harness. This the only harness (that I know of right now) specifically made for the 2019 HD Rams. If you follow in my footsteps, there is an easy way to install this thing without having midget hands, and 6 jointed arms.
You are going to want to remove the small panel to the left of the steering wheel that contains the headlight switch, and dash dimmers. Once that is removed, the STAR connectors are directly behind the now open space. Dont do what I did, and pay attention to which STAR block is green/white and which one is green/black. Make sure you plug the correct plug into each one (they are labeled). The Green/Black one is viable in the picture, the White/Green one is directly behind that. You will know you did it wrong when your truck freaks out, and you are pretty sure you just broke your brand new truck.
Once your harness is installed, pick your programmer of choice (I used a Tazer), and get to work fixing your speedo and TMPS. I did notice the transmission feels better after getting the speedo calibrated! I am within 0.5 mph of my GPS at 70mph, so I will take it!
Side note about the Tazer, it has the option to enable factory auxiliary switch menus on the cluster, meaning you can add the switches, and then control them (latching, momentary, etc). The gentleman from 4th Gen Ram Electronics has a retrofit kit coming out shortly that will allow me to cleanly add 6 auxiliary circuits (30 amps each).