Originally Posted by SeanR

I usually can replace the defrost actuator with out removing the pod. Granted, getting the new actuator in and the cap on so it seals can be a trial, but it's not necessary to remove the pod. You can access the top of the cap with the pod in the upper most position and the lower while hanging out upside down under it.

Take the vacuum line off, pop the cap out of the way, disconnect the arm on the defrost assembly and pull it out. Be gentle putting the new one in and pay particular attention to the diaphragm rubber ring, if it's not all the way around the cap do not force the cap on. Doing so may destroy the diaphragm.