Accessing blower/vents: Squirrel nests!

For the second time this fall, damn squirrels have tried to build a nest under my hood and blocked up the blower. Last time I took it to the dealer and they somewhere under the dash and vaccumed out the heat/ac ducts and the blower. The blower resister had also gone out. $200!!!!!! Now I am having the same problem. How do I access the blower and ducts to vaccum out the leaves? Thanks.