One solid way to find a leak is to drown it with a hose while looking around the area.

Its hard to ignore how common it is for the windshield to leak, there are a handful of videos on line.
I suppose it could be cab lights or a sunroof leak, which would require pulling the headliner.

 

I have no cab lights or sunroof, so most likely the windshield. I have some health issues so I didn't want to crawl under the dash unless necessary, which the hose test would require. But that seems like the next logical step in resolving the problem. Thanks for the input!

 

Sorry to confirm the bad news.

Thanks to technology you could also just stick a gopro down there.
You might also see it if you pull the A pillars.

I've seen some success where people pull the "beauty ring" off the windshield and reseal it, the reality is that my insurance replaces them for $100 so its a cheap fix and not worth the time to chase it down.

 

Just so we're clear on the location, are you talking about the left side of the driver-side or passenger-side footwell? If it's on the passenger-side there are some other possible sources on the table.

 

Glass is "glued" to the cab with a urethane adhesive -- flexing of the cab can pop that loose

Try pushing on the inside of the window , while looking for movement at the outside

 

One of the "Glass Guys" can come to your truck -- pull out your glass and re-seal in a short time -- job will be done right -- with no half a** window sealer junk

 

This is on the left of the driver on the driver side. The DS front corner of the cab. And I also have a pretty nice bore scope I may be able to use that would help me too. Thanks for the feedback and suggestions folks. I'll let you know what I find when I wrestle it this weekend.