560sl Defrost Flaps

According to my repair cd, in order to replace the vacuum servo that operates the defrost flap... you must remove the "instrument panel."

Can I get around this by going through the instrument pod and the glove box? How many servo's must I replace to get the defrost flaps to close when I'm not using the defrost button? How many defrost flaps are there?

Any help is greatly appreciated.

Michael B