... the g1000 small nav button push? Pressing it changes the blue cursor from one nav to the other.

 

-Dave

Have you checked the FSX SDK?

Yep. It's not any of the KEY_G100_PFD_ ones. nor KEY_NAV1_RADIO_SWAP. Unless I am missing something. Pushing the small nav button is supposed to change the NAV being tuned (changing the blue outline).

OK, answer is that there is no SIMCONNECT event. It is a local gauge variable (L:SelectedNav2) that can be changed via FSUIPC macro.