Finally found where the rain was leaking in

[68gmsee]

Something to look.

It wasn't a bad leak. A little water puddling on the floor board and some inside the glove box. Yesterday we had a good storm and I took the glove box out to see if I could detect residual moisture and found it coming from a small weep hole under the bottom of the rear dash pad panel (first pic).

I originally had thought it was the drip channels, windshield seal or the vent openings but after I took the vent cowling off I noticed that the seam from the firewall to the cab just under the windshield was not sealed properly and allowing rain in when it rained hard (second pic). You can see where I sealed it already.