Just in case anyone is curious...on our 1999 Sundancer 450 the main head is on the port side and the galley is on the starboard side. The blowers for the second head and the galley are, of course over there behind the refrigerator.
The port side head blower is behind a small panel at the back of the medicine cabinet above the sink. The opening is about 8" X 4". Very limited access. super difficult to get out. Had to blindly find the mounting screws and get them out. Next challenge was getting the blower out of the access hole. Had to take it apart before it would come out. Anything you drop is likely gone (there's a flashlight down there that is probably running out of charge right about now).
Super difficult but not impossible.