Having condensation under carpet between floor metal and carpet pad. I've been looking for leaks. No luck. Why is this happening! It looks more like condensation than a leak. . well, I guess I'll go look again. ..

 

Common problem with 2 potential causes. Either the third brake light is leaking, or the a.c. condensate tube is clogged on the firewall.
If it's the brake light, clear silicone will do the trick.
If the condensate tube, there is a tsb to fix it. All it needs is a blast from an air compressor and a 90° elbow

 

take off inner fender to get to it?

 

Replaced my 90 Deg elbo from underneath truck. Removed nothing.

Another reported leak path was through seam or pinhole in front passenger door weather stripping at bottom of door. Not been long since I saw that post.