The answer is simple.

Look under the directional vent in frot of the seat.

You'll see a 1/2-3/4 plastic strip attached to the heater cover that
runs under that vent.

Using an Exacto razor saw, or anything else that is sharp, cut this
plastic strip outa there.
Doesn't have to be pretty right this second.

Take the srcews out of the sides of the cover, and pull it straight up.

Do whatever your gonna do, and clean up the cut with anything you want
to use , and fasten the cover back down to the floor under the seat.

Your done with this crazy project.

I know this is in the archives.
I did this 5 years ago and thought it was an insane project to yank the
seat to get to the heater then, as I do now.