I posted a smiliar note yesterday but see it did not register. I wish to thank those who responded to my query regarding the acorn nest in the cabin air filter box. I appreciated the schematics presented and the other thoughts. I was able to finally locate the actual intake point in the firewall by removing some of the plastic grids and shining a flash in the direction of the cabin filter box, then viewing the light from the box. I still cannot see how the critter made his entry, as all plastic grills and trim seem to be intact and in place. I have decided to keep the car garaged for the next few weeks until snow cover, and have also located some easy roast squirrel recipes. I will keep an eye on this site for any additional suggestions. Thanks for your help.