So no one said this would be easy, but finally got my OVMS set up and installed. Without disconnecting the TCU module ( behind my glove box) the remote lock and unlock worked but not the A/C on / off portion. So I took out the glove box and disconnected the TCU. Upon doing so, the A/C one/ off worked, I was able to see all features on the OVMS app. However the voice recognition in the car no longer worked and I was no longer receiving text messages in the car. After searching through various wiring diagrams, I deduced that one of the wires in the TCU was for the voice recognition system, but which one? Does anyone have a wiring diagram for the 2016 Nissan leaf SL that shows which wire in the TCU module is the voice recognition one? Or is there an adapter available that will allow me to bypass all the other functions in the TCU but allow the voice recognition to work? It is not a big deal as I can use Bixby on my Samsung to dial out, but still just wondering.
As I mentioned in a different (related) thread: Not all 2016 Leafs are created equal as they moved the TCU from the EV CAN bus to the CAR CAN bus during this model year.
Unfortunately, you can't "pick and choose" the TCU functions you want: you either disconnect it or not, resulting in the functionality you have observed. Seems like most people prioritize climate control functionality over the telecom. YMMV.