I have an '05 Winni Adventurer, so believe removal of unit would be the same. That is it slides out, accessed by removing a couple of bolts holding
hinged panel surrounding the rad. Once that is hinged up out of the way there are a number of bolts holding the unit in place that then have to be removed. Moving this unit is no easy task as it weighs close to 200#.
A chap posted a number of step by step photos of the procedure a few years ago on IRV2. I used them to help guide the chap who removed mine
for what turned out to be a seized inner blower bearing.
Check for some older postings on this subject, you may get lucky.
I'll see if i can find my download of the source of the photos as well.
You might also want to check "Airexcel" site.