Water leak

There is water coming in from in between the seem that connects the rear window to the cab on the top. The carpet on the drivers side is getting wet somehow to but I can't find any leaks over there. Can anyone help me out on how to fix these problems? I've gotten a quote on a professional job finding and fixing leaks but if possible I'd like to do it myself.
Thanks!

 

You could try to run a silicone bead around the rear window .

 

Sure it is the window leaking and not the 3rd brake light? 3rd brake light has been an area that has had some leaks.
Remove it, install a new seal and then reinstall. Id try that first unless you are sure it is the window. If it is the window, get a windshield shop to fix, remove it, new seals, reinstall.

 

Start here:

https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

And visit here for your issues today:

https://www.tundras.com/threads/definitive-2000-2006-cab-area-rain-water-leak-thread.70464/

 

Since it's the rear window I'd start with the brake light seal.