[KevinH1990]

Because you recently bought the car, you don't know what a previous owner might have done. I suggest that you consider two possibilities.

(1) A common failure point on 986's is the ignition switch. To replace the ignition switch usually requires the removal of the duct that supplies the driver's side air vent. It's possible that that someone replaced the ignition switch and failed to reinstall the duct correctly. It is fairly easy to remove the duct by compressing the bellows-like part of the tube near the end. You might find that the duct was oriented incorrectly.

(2) A second problem with the 986 is that Porsche covered the dampers that control air flow with a foam substance that deteriorates over time. Most long-term owners have experienced detached foam flying out of the vents at some point in their stewardship. You can find several videos on YouTube showing techniques for replacing the foam on the dampers. It's possible that a substantial amount of detached foam is preventing the free flow of air to the vent in question or that a previous owner didn't remove the old foam properly or otherwise bungled the repair causing a blockage.

Good luck with your research and I hope one of these suggestions helps.