Can't find where source is. Door seems fine. Any suggestions?

 

Was it out in the rain? If so, it could be the seal on window or door. Can also come in from behind the dash. Depends on how much crudd & leaves are stuffed in the seals. If not in the rain, maybe the thermostat.

 

Grommet from where your wires come in from the firewall? Also you sure your window seals are not dry rotted? Mines are shot and it drips water in the speaker hole when it starts pouring.

 

I have sat inside with water hose spraying on top. I know for sure its not around door. I have wires running through grommet in firewall. That may be culprit. Will try to seal that

 

Ok yea Im willing to bet thats the case if you have extra wires running through it. Mines did it until I sealed it up. You can jsut get a bit of black silicone and dab a bit there. Works like a charm.

 

Is the floor completely wet all the way through to the back seat or it just kind of damp in the front?

 

As far as I can tell just drivers floor. Its not damp. Its soaked

 

I had the same issue, but it was wet all the way back. My driver rear window would roll down just enough from a bad vibration I had. Not saying thats your issue, but it could be something with the back door if it's wet back there too. Probly not much help, but another idea if the others don't work.