where is the ac/heater fan motor located and is it necessary to remove the entire dash?

Same year Camry blower motor is located just behind the black hush panel - below the glove box. Hush panel un-clips using flat blade screwdriver then it can be removed and laid aside. Then there is a wire connector to the blower motor and 3 bolts holding the blower assembly into place - The 3 bolts takes 8 mm (optional 5/16) socket, a 4 inch extension and a ratchet - all in 1/4 inch drive. Skilled mechanic = 20 minutes ... DIYer with a few skills = 40 minutes tops. I do not think the Avalon is any different. Good luck!