I have a leak any time it rains on the driver's side floor. It does not appear to run up the firewall very high. There is no rust around the windshield and the gasket is tight; the winshield wiper shaft is [relatively] tight. The door gasket is soaked up to about a foot from the floor. I have the truck inside the garage with a dehumidifier going in it to completely dry it out and will troubleshoot next weekend.
A poster on another board suggested the heater box drains might be blocked. The drain channel under the back of the hood was full of leaves and I blew them out and removed several from the heater box. Does anybody know where the drains from the heater box empty out so I can try blowing them out? I have removed the door gasket to dry and will reinstall it; the spring in the gasket had been crushed in a couple of places and may not be sealing properly.
Any ideas appreciated.