What's this thing?

I can make out a frequency number, which tells me it's an RF device. Which pretty much limits it to smart key or key fob-related.

 

The source of your leak is two likely/common places.

1. At the upper corner of the hatch area, where water drains at the sides of the hatch, there are body seams. They tend to develop cracks.
2. On each side of the hatch, where the lift cylinders mount, debris tends to gather and acts like a dam. Water builds up behind the dam and can leak in where the cylinder is mounted.

Both of these result in water leaking down the inside of the trunk trim panels, into the 12v battery well, into the storage cubby, into the spare tire storage area, etc. I even had about a cup of water pour out of the HV battery fan duct work one time when swapping out a customers battery.

 

I've only had very minor leakage/puddling under the driver side storage cubby so far. I drilled one 1/8th inch hole in each side area, at what looked like the lowest spot, to prevent any buildup. So far, so good.

 

The part in question has a Toyota part number in it. If you type the number into a Toyota parts site it will tell you what it is. I can’t read the numbers well enough to run it down but it’s the first line on the sticker.

 

https://www.toyotapartsdeal.com/oem/toyota~oscillator~indoor~electrical~key~89992-47040.html

 

Check the 12 volt battery hole its probably full of water. If you garage the car you can remove the rubber drain plug at the bottom of that battery well. You can also remove the rubber drain plug under the spare tire but only if you garage the car. If not I would be leery of removing those plugs as mice love to inhabit a G2. If the car lives outside I would check the air cabin filter behind the glove box for signs of mice.
Very common for mice in a G2 they love the taste of the wiring and will do alot of damage mice inhabitation seem to go hand in hand with cabin leaks.

I believe that white box your referring to is the SKS antenna amplifier. There's a few of those in the car.

 

If you have not already, you should pull up the plastic black strips in the channels on the roof. The seam that leaks runs the length of the roof and the cracks on mine went up about an inch under those strips. Once I did that and sealed the cracks, I have had a totally dry hatch.

 

Jessie is right. Those black strips pop right off just pull them up and off. They snap right back on. It may help to then wash the car clean out that valley real good and give it a good look maybe use a magnifier and if really unlucky you will see a crack running up that valley. Mine is only cracked at the pass side hatch corner.

I suspect its cracking there from slamming the trunk closed alot which is hard not to slam the trunk really. Or maybe its just a high body flex area but cracks there on a G2 are very very common. Mine drips down on the 12 volt battery side but mine is garaged so no big deal for me.

 

Three areas for water entry into trunk, that can and has spilled into other areas of the car.

1) Most common source of leaks: just under the black decorative strip near the hatch glass

• Read this thread in entirety so you can duplicate the trouble shooting steps) https://priuschat.com/threads/water-filling-driver-side-floor-pan.140242/.
• See Post #49; very good pictures showing hatch cracks.

​

2) Less common source of leaks: failed weather seals

• See Post #23. Pictures show where water was entering, b/c the external seals are all flat and no longer able to do their job: SEAL.
• See Post #121. Water likely entering b/c of bad body work. Body shop likely reused the bumper fasteners that are probably inteded to be reused once b/c of the weather seals.
• READ this in Entirety; its short w/ good pictures! This thread really highlights the problem with reusing part that has a worn out seal. BEST to just make your own (cheap) vs buying new clips/seals from dealer (expesive).

Buy the rubberized door weather stripping tape seal from Lowe's/Home Depot/Ace Hardware/etc; DO NOT BUY THE GREY FOAM, it will become compressed quickly. You may have to get both b/c 1/8in difference in thickness is small, but sometimes, it can be enough from pushing/screwing the part back on.
3/8in thick * 3/4in wide * 10ft long self adhesive roll, $6
1/4in (2/8in) thick * 3/4in wide * 10ft long self adhesive roll, $5

​

3) Bad bady work.

See Post #121. Picture shows area body shop likely missed b/c water is entering from here. Apparently the weld/seals separated enough for water to enter, but not be visibly damaged to become part of a repair. Owner found out the hard way. Another area to be looking out for.​