I was installing a cable on the battery pack to run my UPS system during blackouts. I noticed this connector in the driver's side rear wheel well. I was hoping someone could identify it.
It is junction connector J30. It's a splice pack that provides ground from Ground BL to the inside and outside luggage compartment oscillators (when equipped with Smart Entry), door control receiver, luggage compartment courtesy switch, luggage compartment door lock motor, left front buckle switch, and the battery ECU, on USA models. As you can see, all the wires are White with a Black stripe, often used by Toyota for ground. Under the blue cap are bussed terminals, which in this case, tie all the individual circuits together.