I *finally* made time to investigate this. A central vent appears to feed both sides of the window defroster vents, so I considered other reasons air wouldn't reach the driver's side. It ended up being caused by the vent door, or whatever mechanism routes the air up or to the dash vents or to...

Thanks for the response, tametalon92. I'll check it out. I hope it's leaves, not the remains of some critter.

The problem: My new-to-me 91 Talon won't defrost the driver's side of the windshield.Will someone please post a diagram or pics of how a 1G DSM's hvac ducts should look under the dash? The heat works, and the passenger's side of the windshield will defrost, so I figure I'm missing one or more...