how do i replace the cabin air filter for my 2003 toyota avalon

In the 2001 Avalon the filter is located behind the glove box. The hardest part of the job is detaching the box so it drops down enough to allow access. The replacement is really easy once you have the access. The trick is to "unhinge" the box without breaking the upper attachments. The manual wasn't very helpful other than to show me where it was located. If your handy and careful it is a DYI project. If your wary of breaking something, maybe you can ask someone to show you how to do it once. After that you'll know the "secret" and lowering the glove box is easy. I found that changing the cabin air filter does make the interior smell a little bit better. .

There are some good videos on youtube. When putting it back, focus on the lower right corner first, tucking it inside the plastic. Next put the 3 screws along the top edge. When replacing the underneath panel, the leftmost clip thing is done last.