[Lumps!] climate control

Got a new problem. 89XJS, I’ve got the a/c working so well that the air
leaking out thru the defrosts vents is causing big time condensation on the
windshield in our hot and stuffy Atlanta. Is there some kind of gasket on
these doors for defrost. How do I get to them and where do I begin on
troubleshooting this problem

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