I've got a 2000 Legacy, 150k M/T, and the air recirculation motor was making a loud click-click-click sound recently, so I tore into the car trying to find it.  RIght now the glove box, blower motor, and center console cover are out.  I see the flap actuator, but it's on the blower motor housing, pushed up against the passenger-side area near the fender.  I can't really get to it very well, and the housing seems to be fused to the heater core.

 

My Haynes manual says that I must drain the coolant, remove the dash, the instrument panel, and the support bar under the dash before I can remove the heater core / blower motor housing.  It's a hell of a job, and now the bloody actuator isn't even making the click sound anymore (no blown fuse, not in defrost mode).  I presume that, at this point, I need to change out the actuator.

 

My question: Do I really need to do all this to fix this problem?  I've found people reporting similar issues with the recirculation flap/actuator, though I can't find that particular post now.  Does anyone have experience with this issue?

Heater core/ blower motor housing is all one unit and yes, the dash has to come completely out to remove it.

 

You may get some extra room by removing the bolts/nuts on the lower corner of the dash on that side. This will allow you to pull the corner of the dash out about an inch and a half (don't pull too far or the dash may get damaged) and may give you room to get to the actuator or remove other bits. I know on the older models there is a control module of some sort over there.

 

You might also try fishing around in the blower housing to see if there are leaves, acorns, dead mouse, etc., down in there blocking the flap.

 

You could also remove the wiper cowl and try going in through the vent in the firewall.

Sorry, nothing to add but in another recent post a link describes the steps for dash removal/access heater core process that bemoans that Subaru starts with the heater core and then builds the entire car around it.