Where/What does one start to look for when there's no air flow (heat) to floor on a 84 300D?

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1984 300D, 1972 LT1 Corvette, 2014 Artic White 3LT/Z51 C7, 2013 650i Convertible BMW, 1994 Kawasaki Vulcan, 1992 Yamaha Seca II and 1996 Dodge Ram 2500.

Vacuum pod. On the drivers side, basically on top of the tunnel, there is a vacuum pod that sits sideways. Select floor heat and put a vacuum gauge on the hose to it. Or use a vacuum pump to see if it actuates and holds a vacuum.

Thank you! I will look into it...

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1984 300D, 1972 LT1 Corvette, 2014 Artic White 3LT/Z51 C7, 2013 650i Convertible BMW, 1994 Kawasaki Vulcan, 1992 Yamaha Seca II and 1996 Dodge Ram 2500.