The fan motor is going strong but almost no air is coming out of the vents. My local dealer claimed to have fixed it at a cost of $777, but it has returned. I have since moved a thousand miles away. ideas?

 

Reads like an air flap is not working right. No direct experience with the A/C system in either in my Boxster or 996 Turbo -- both systems never manifested any problems thankfully -- but there are a number of air flaps that are under manual control -- via the buttons on the A/C panel -- or under automatic control when the system is in auto climate mode.

If the fan is running and no air is coming from any of the vents -- have you tried manually selecting the vents under the windshield, the center vents, then the vents under the dash? -- at least one air flap, its "motor" -- is not working.

I would think a Porsche service department tech could query the A/C controller for any error codes -- or possibly even cause it to preform some self-test and report back the results. From this then the tech would have some idea of what is going on.

Or even more likely the tech has seen this behavior before and knows what is wrong.

Be sure you take the paperwork of the previous work with you. There should be a warranty on the labor and parts used. If a replaced part has failed then this might be covered under warranty.