My windshield leaks. It is directly above the steering wheel and when I turn hard left, it runs out of the seal and dribbles down onto the steering wheel and onto the gearshift.
If you get under the dash, you most likely have a leak drooling on top of the electronics on the left kickpanel (behind it, up high) and your floorboard will be wet.
This is a bad seal on the windshield.
Mine leaks because the PO had a shytty installer do the work and they scored around the old glass when pulling it out and scratched the paint, causing the perimeter of my windshield frame to rust. I now have significant corrosion around it.
I'm preparing to take it to a body shop and paying $2500 to pull the windshield, cut out the rust, weld in new material, rust converter, epoxy primer and paint the entire frame, hood, and cowl up past the sunroof, and replace with a new windshield. I will supply the Toyota seal, a new hood, new hood seals, and I will remove the headliner, sunroof, and all windshield trim to they can do all necessary short of removing the dash.
The installer didn't do it right. He didn't use sealer between the glass and seal AND the seal and frame. The instructions in the FSM are crystal F'n clear on how it has to be done. If not, it WILL leak. They will ALWAYS tell you they know what they are doing and do it every day.
Make THEM tape off the sunroof, use a garden hose from the top and pour it over the windshield when the nose of the truck is pointing down, and it will seep in behind the gasket at the top left of the windshield.
They're full of shyt and trying to make you think you're crazy.
Be the biggest pain in this guy's ass you can possibly be until it's done right.
I've had two shops tell me to pound sand because I told them how it needs to be done and they refused. F them. I make sure that everyone in our local clubs know what glass shops NOT to go to.
Print off the pages in the FSM and take them to him and walk through STEP BY STEP what he did and didn't do. Have the actual person that did the install stand there and watch him while you go through this. Body language will tell the story.