Leaking Cab....

It could be coming from around the extra cab door seals. Try checking those.

yes the third brake light at the top rear of the cab may have lost its seal which will pour water into the top rails and then it runs to the lowest part before pouring out

The problem is water leaks at the belt type molding on the outside on both sides I've been troubleshooting one for 2 days and this is the rear power window on the back of the cab replaced both inside and outside moldings and it still leaks and there actually is no drain so I added one very old design

Hey, here's the deal, the water is coming in at the third brake light. For me the problem started shortly after I began going to the drive through carwash. Those flanging beater there at the carwash agitated and loosened up the sealed moulding around that third brake light and it started leaking. I tried everything, at first, and the leak was still there. I then contacted Toyota about whether or not there had been any reported problems of this type, with no real help. I then figured it had to be the brake light, which I had changed out, and the leak stopped. That was two years ago (2017)

I had the same problem. It’s a factory defect with the third brake light. The gasket around the light goes bad. You can buy a new light, BUT you can’t buy the gasket. Not even from the factory or dealership. My solution was to buy a spray can of Flex seal. I used painters tape and taped off the area and the light. Then sprayed around the edge of the light. Works great and I was able to stop the leak for under $10. There are videos on YouTube that show how difficult it is to remove the entire housing of the third break light. Not worth it. You have to remove the headliner to get to the screws to remove the light. Hope this helps. Good luck

I replaced the third light which came with new gasket. I have the center sliding window and not the power window but it wasnt too bad as Pineappler3 states; Just need patience. Still tiny leak I believe is coming thru window seal. Still researching how to fix it without replacing entire window