You need a wiring diagram for your year Outback. These are available from eBay sellers, usually less than $10. If you are adding additional load to a circuit that is not designed for the load it will really come in handy.
There is no relay used on the speedometer circuit.
Subaru Outback was created in 1995.
The Subaru Outback is sold in the US.
The 2013 Subaru Outback has 16 valves.
The 2002 Subaru Outback has 16 valves.
The 2001 Subaru Outback has 16 valves.
The 2011 Subaru Outback has 16 valves.
The 2005 Subaru Outback has 16 valves.
The 2007 Subaru Outback has 16 valves.
The 2004 Subaru Outback has 16 valves.
The 2006 Subaru Outback has 16 valves.
The 2009 Subaru Outback has 16 valves.