Here are photos & notes on how I added paddle shifters to my 08 H6 Outback. For 2008-2009, the Legacy with H6 or turbo, with automatic, came factory equipped with paddle shifters. These powertrains were available on Outbacks, but they did not come with the paddle shifters.
This is not a difficult retrofit, but the driver's airbag module & steering wheel are removed & reinstalled in the course of the modification. All applicable instructions & guidelines in the Factory Service Manual (FSM) must be followed to ensure that airbag & steering function are correctly restored upon reassembly.
The organization of the factory parts diagrams is a bit unintuitive. The paddle assembly & screws are shown here and the clamshell column shroud is shown here.
You need
REVIEW THE FSM FOR AIRBAG HANDLING PRECAUTIONS! There are guidelines for disconnecting the battery & even a correct orientation to sit the module while it's removed from the car.
The airbag/horn assembly is held in place with a recessed torx screw on each side. Pick the correct torx bit, seat it fully & unscrew it firmly. There's not much torque holding it in, but you sure don't want to strip the head. I used a 1/4" socket & extension & they came loose easily.
Those torx screws are captive so they won't fall out once unscrewed. You can see where they screw into & you can see the left side captive torx screw.
The yellow locking caps of the airbag connectors are gently pried open with a small screwdriver, then the 2 connecters will detach from the airbag module. The single wire for horn has a small retention tab that can be released with a small screwdriver.
The steering wheel retaining nut took a few attempts to loosen. You want to hold the wheel steady while you bear against the nut, you don't want the force of your wrench making the pinion bear against the rack. Control the wrench to prevent it slipping off & damaging expensive items like the wheel or gauge cluster.
I didn't have a suitable puller, so I loosened the nut but left it on & removed the wheel by very carefully rocking & pulling by hand. Once it came loose of the splines, I removed the nut, made a scribe mark & removed the wheel. As long as you're parked with the wheel & tires perfectly straight ahead, you can probably eyeball the reinstallation of the steering wheel- if it's off by a full spline, it will be obvious.
The airbag connecters are integral to the clockspring/roll connector. All other wiring for steering wheel buttons stays with the steering wheel. There is 1 screw holding on the lower clamshell, plus pegs & snap tabs the whole way around its seam. With the lower clamshell removed, the upper clamshell is held on with 3 screws that are difficult to reach & even more difficult to reinstall.
I have the factory remote start so my 6-wire ignition switch connector is routed differently.
5 identical screws attach the paddle assembly to the column. The upper 2 are already holding the roll connecter in place, so they are removed then reinstalled once the paddles are in place. The yellow arrows show locating pegs for positioning the paddle assembly.
The inside of the upper clamshell shows the 3 bosses where the screws go. The bosses have tabs that engage in the steering column metal supports so that tightening the screws won't twist & break the bosses. Press the clamshell down while installing the screws & let those tabs do their job.
I installed & removed the screws to cut the threads before installing the upper clamshell. There's no easy access for your screwdriver to install those 3 screws. At least one of them I ended up using a screwdriver bit & turning it with my fingers to get it started. With the screws mostly installed I could finally angle a screwdriver in there for the final tightening. After your wiring is in place, align the lower clamshell & press the pegs & tabs together, then install the single screw from below.
The wires for the paddle switches were not present in my steering column & I wanted to wire them up as OEM as possible without cutting the wires on the paddle assembly.
Many of the compact, high-density, small gauge connectors in a Subaru are made by Yazaki. Their business philosophy seems to be- do everything possible to prevent consumers from obtaining our products. If Mouser or Digi-Key carried this stuff, it would be easy to get 1 or 2 for a mod, but I never found any outlet that officially sells these connectors, just a few places that might have odd quantities of random sizes. Yazaki's own website lists sales reps in the US for "small quantities" but I called & basically got laughed at, since "small quantity" means something like "only" 10,000 of a part.
I finally found a guy in Japan selling electrical bits for motorcycle owners & he had the correct 3-position plug to mate with the socket on the paddle switch assembly. I had a 4 conductor loom in my computer parts bin that was long enough, so I just taped back the 4th wire. The female terminals are *tiny* & it was delicate work with a fine jewelers pliers to get them properly crimped. I was able to pull the loom through existing plastic raceways that route wiring down the steering column & into the dash.
I ended up buying several of this connector & its pins to reach a minimum order. If someone is doing this mod & wants the correct connector I will resell them for what I have into them.
The FSM wiring diagrams show that the paddle switches are in parallel with the +/- switches on the console shifter- the computer doesn't even know if an up/down request came from the paddles or the gearshift. The +/- signal lines connect to the body integrated unit at the base of the steering column & the BIU relays shift requests to the transmission computer over the CANBUS.
With the FSM I could confirm the wire colors & the connector positions to positively indentify the +/- wires at the BIU. I carefully sliced away some insulation & soldered my new wires on, then wrapped with tape & secured with a zip tie. The common wire on the paddle assembly is ground, so I just connected that to a ring terminal on one of the BIU hold-down nuts.
Everything went back together smoothly & all is working correctly. You can make shift requests with the paddles even with the console shifter in "D" - the display changes from "D" to a number & it's pretty intuitive about changing back to "D" based on time passed & throttle activity. It also seems smart about engine braking- if I paddle it down to "4" & keep my foot off the gas, it seems to hold "4" until after I apply some throttle.