from looking around on the web some on this,
It seems the 12v accessory is the grey wire,
and blue is the 12v constant.
seems to be the same for 95% of the newer toyotas.
so youd tap into the gray.
for confirmation, id recommend hitting up a harbor freight and picking up a 4.00 multimeter and check the pins.
HARBOR FREIGHT MULTI METER
you should only get voltage on the pin when the car is on