Leaking rear water from top right of rear window

When it rains the right side under my seat has been getting wet. I finally realized that the top of the cab on the passenger side is getting wet... anyone have this issue with second gens maybe specifically regular cabs?

 

It is probably from the third brake seal light above the rear window....

 

i had this issue on my 2012 same location you have pictured, where it would just cry a few tear drops of water

in my case it was not the third brake light, but where the roof molding strip meets the corner of the rear window seal

I basically removed the interior in that entire area on a dry day, and then started water testing spots until I found the exact spot and could duplicate the leak

that top corner where the window pops into the cab was the exact spot in my case, if you pull the trim and look right behind the headliner in that are you will see what I am talking about

 

How did you fix it?

 

well at first I had a local auto glass guy come over to take a look because I wanted the entire thing removed and replaced
realizing that was a little ridiculous, he suggested putting a little dab of some product with a syringe right in the spot where the little clip would drip water
I was reluctant at first, I did not like the idea of trying to seal a leak from the inside IMHO is more just a patch job
but no leakage at the moment and I have tested it aggressively, though my guess is I will have to revisit this in the future at some point

I would bet that its a combination of dry rotting cracked rubber and plastic that caused this, mixed with an area that is prone to mildew in many cases/environments
The area between the back of the cab and the front of the cap has a tendency to get this way quickly in moist areas

 

I'll try this, what can I do to fix?

 

first confirm it is in fact leaking from that point before trying to fix anything

if you remove some of the rear interior trim you can pull the headliner down a few inches to have a look
have someone with a garden hose outside and you get in and close the doors
you should be able to find the trouble spot right away

 

Verify as in the post above here. Then if it is leaking I don't think Toyota sells a gasket for this as it is glued to the light assembly and the truck body. Two options: Remove the light, clean the body and light of gasket and adhesive then seal it back on with silicone adhesive. OR purchase a new third brake light assembly and install it.

Note there are also aftermarket lights that are cheaper than OEM.

 

of course not ruling out the brake light without proper testing

but its kinda rare to find a 2nd gen with a leaking 3rd brake light

the 3rd gen tacoma however, now that is an issue with toyota acknowledging the problem and releasing a tsb