I just confirmed with my multimeter that that pin 11 does indeed seem to provide constant and pin 16 switched. Many thanks for this info. Now my next task is deciding how to tap it, either with OBD splitter or tapping the wires somewhere behind.Now that I have access to a refresh wiring diagram (tesla took forever to publish these), it appears there is both switched and unswitched power on the standard obdii port. The normal + pin, which is pin 16 has switched power, but Tesla used one of the mfg option pins, pin 11, as unswitched power.
I just learned this after reviewing the diagrams yesterday, so have not yet confirmed in my own car.