I have a 07 legacy doing the same thing. I flushed the heater core by romoving the hoses and running pressured (water hose) water through the heater core. refilled heater core with hoses off to remove any air bubles. heats on both sides now.
in the engine bay. Passenger side. Near the strut tower.
The 2007 Subaru Outback has a flat 4 engine.
The 2009 Subaru Outback has a flat 4 engine.
The 2013 Subaru Outback has a flat 4 engine.
The 2012 Subaru Outback has a flat 4 engine.
The 2006 Subaru Outback has a flat 4 engine.
The 2003 Subaru Outback has a flat 4 engine.
The 2005 Subaru Outback has a flat 4 engine.
The 2004 Subaru Outback has a flat 4 engine.
The 2002 Subaru Outback has a flat 4 engine.
The 2011 Subaru Outback has a flat 4 engine.
The 2014 Subaru Outback has a flat 4 engine.