Front seat has its massage stopped at the top bladder. Read it may be the PRV valve. Went to go tackle this but the write up that covers seat back removal is for older vehicles.

Anyone have instructions for removal?

That was easy. For newer l405s with controls not on the seat there are 2 torx bit screws on the bottom of the seat holding the rear cover in place. I removed the two screws and the back basically fell out.

Very easy.

Now for diagnosing the massaging issue.