Getting to the AC recirculation valve/flap

GM,

As the topic says, I would like to reach the recirculation valve of my AC system. The reason being air from outside is getting into the car even when the valve is engaged. I was successful in dismantling the blower motor but just not able to take it any further. I can reach my hands to the valves and can feel the edges on the valve which have been clearly chewed off by rats, leaving gaps through which air from the outside is being sucked into the car, very annoying.

Any one here know how to get this thing off please? Do I need to get the dash off to reach this part?

Thank you.