Water leak inside 93 Grand Am Se

The water comes in behind the glove box. We found out where when all the shit in the box was soaked after washing the car.

My question is why, and how hard to fix is it? I'm no mechanic, but would like to fix it myself. My 96 GA GT leaks as well, but on the drivers side mainly.

This is a common leak area on Grand Ams. The leak comes from the wiring grommet-holes where wires come through the firewall. My advice would be to caulk the living shit out of each hole where there's wires - you'll probably want to find some kind of 'high heat' caulk too.

Additional thought, look close at the windshield weatherstriiping.

Pull the black trim at the bottom of the windshield off, make sure there is nothing caught behind it leaves, bugs, other assorted crap. check it to make sure it fits the windshield, if it doesn't, try to find one off a wreck that fits right, often they crack and warp and leak into the defroster ducts and onto the wiring grommets.

Thanks. Will check and get back to let you know how it goes.