Leak in trunk

IIRC someone recently found it leaking from one of the grommets that screws go into. Either screw for the bumper or tail light, can't recall.

 

It's either/both the seal for the trunk lid, or the seal around the tail light assembly.
There are several videos on youtube about it.
Slight possibility you could have a crack.

You could empty the trunk compartment, have someone craw in from the rear seat
as someone uses a water hose around the whole trunk lid and tail lights...
You should be able to see where it's leaking from....

You may have to remove some of the trim pieces to pin point it.

 

If you pull a couple of screws out including those hooks you'll be able to bend just a little bit that piece of material or you can take it all off if you want I just bend it in and put a brick or a toolbox or something that will hold it open for me and then you're looking right at where the tail light mounts and some three dimensional unit construction water like everyone is saying is probably coming from either The deck lid seal or a long where the spoiler mounts or the tail light but the tail light is kind of a stretch here unless you're cars living in the car wash or something and water is getting sprayed on that tail light I would think more the trunk hat seal area and or where the spoiler mounts I've noticed on the 13 that that's really flimsy but those are usually the spoiler clips into these clear things at least it does on the Gen 2 it's probably very similar here and I know that it's crap builds up at the bottom edge of the spoiler right at the bottom of the glass water can get held up there and I can't imagine that being a good thing so it's important to keep that clean I regularly see Prius. No matter the model or generation come to me with the rear hat seal you can't even see where the seal begins and the body starts It is full of tree crap level with the seal it must be 5 lb of it in there all around the seal until it starts to turn vertical like where the tail lights are and drops that area will just be dirty but the rest of them are level The door seal is barely doing any work It is so full in that area It is unbelievable.

 

Yeah less photoshop and more opening up needed, lol.

Is it parked outside all the time? Near trees?

what region btw?

 

Is water standing in the space under and around the battery? In my experience, that will happen if the drain passage between taillight and body sheet metal gets clogged with tree junk. The solution is to remove the taillight assembly and clean the debris out.

 

I just go to the Toyota dealer. They have been great for me.
Once they have your VIN number they should have no problem finding
the correct part.

 

Try a different dealer. What area are you in?
I don't bother with phoning, I go in person. And watch them look it up.