All the 2017,18,19 Milwaukee Eight touring bikes' wiring diagrams are the same. Same wires going to the same BCU, ECU terminal numbers. Same colored wires going to the same numbered connections. The only difference? Amps, Speakers, Police lights and Radios. Why is it so difficult to add a tachometer to these Road Kings? It should be like adding a chassis fan or a CVO rear fender. Take to the dealer and they plug into the data port and allow the extra device, right?? The 3 dealers in the Sacramento area say things like: 1.Can't do it. The BCU and the ECU and blah, blah, blah. 2. We don't know enough about the new can bus systems yet. (What?? Are you kidding me??) 3. Can't add anything to the new can bus systems. (Of course you can, right?) Well, I added the Harley can bus tachometer to my road king and everything works for a while then the tach reads 700-1000 rpms higher than the actual rpms. I have to reset the system (DIAG) to get the tach back to zero. Also, there is a U0157 SPDO (speedometer) error code which means that the 2 devices (tach and speedo) aren't communicating properly with each other. It seems to me that the dealer should be able to add the extra device to the system. After all, my RK is wired the same as the police version of the same model with the same tach and speedometer. Is there anyone out there that knows the can bus system on these Milwaukee 8's to rectify this problem? It's a tachometer! This shouldn't be rocket science.