I want to install a trailer wiring harness for my 2009 Legacy wagon.  I have the "towready" wiring kit (connects to battery) and their 2.5 amp module ( I could not find a "T" connector kit for this vehicle).  Where is a good place to run the wire from the battery through the firewall and  what side do I find the brake wiring.  Thanks in advance for you assistance.

i have a Subaru OEM harness that's plug and play - $25 plus shipping.

 

can you simply find the stock connector that's made for the trailer wiring harness to be plug and play and just use those wires?  a few second search would show which wires are which and then no running the length of the car?

 

if not, should be able to squeeze it through the firewall around the steering column, there's usually a few grommets there you can slit and run through.

 

brakes are on both sides, but i'm not sure what exactly you need for inputs, it may vary by the harness. 

 

does yours have the "converter" box thing or is it just straight wires?

 

there's quite a bit of info on line with wiring instructions and body wiring locations.