How to diag a leaking cab

[obijuank5]

What is the best way to accurately diagnose a water leak? This was with a super light rain and appeared really quickly. It's on the passenger side back wall is where it's showing. Directly above that is the corner for the window and that rubber appears ok.
I don't want to just guess and toss a new back window seal in it for no good reason.

Got any tips on how to actually pinpoint this leak and repair it for good?

 

[ryoken]

garden hose... start pulling interior panels, till the leak is semi obvious... 2 peeps, or lay it on the roof...

 

[rampage]

Hose is the only way I know. Start at the bottom middle and slowly work your way to the corner and up and over again until you find it. A helper would be nice along with some patience.
Can’t tell you how to repair it until you find the problem.

 

[obijuank5]

Turns out the drip rails holes aren't even sealed up at all. So that's cool. Can I just take those off and seal em up?
Some special body sealer or just good ol metal roof NP1? LOL

 

[ryoken]

Turns out the drip rails holes aren't even sealed up at all. So that's cool. Can I just take those off and seal em up?
Some special body sealer or just good ol metal roof NP1? LOL

seam sealer is the best way.. like a Lord Fusor, etc..