Vehicle HVAC system with modular door design

A modular door for a vehicle HVAC system comprising:

• a door plate having a front surface extending between an upper edge surface and a lower edge surface, the upper edge surface defining a first array of keyed orifices and the lower edge surface defining a second array of keyed orifices, wherein the first and second arrays of keyed orifices form pairs of axially aligned keyed orifices, and wherein each of the keyed orifices within each pair axially aligned of keyed orifices has a shape that differs from the keyed orifices that form the other pairs of axially aligned keyed orifices;
• a first shaft having a first keyed protrusion disposed within a first keyed orifice of the first array of keyed orifices;
• and
• a second shaft having a second keyed protrusion disposed within a first keyed orifice of the second array of keyed orifices, wherein the first keyed orifice of the first array of keyed orifices and the first keyed orifice of the second array of keyed orifices form a first pair of the pairs of axially aligned keyed orifices.