[lepa71]

How hard is it to retrofit Turn Signals mirrors caps? What part number are for those?

 

[cfodder]

The retrofit is pretty easy. Having done it twice now (once on the 2016 and once on the 2018), my advice is to NOT remove the mirror lens like some directions suggest. I did that on my 2016 and it took forever (because I was worried I'd break it), and I wasn't sure I actually put it on back right. Just pull the door panel off, unbolt the mirror, run the wires through the mirror housing, add the signal, and put everything back on. To get the wires through, I just used a stiffer wire (I used some #18 bare wire) to pull the wires for the turn signal down through the housing.

For retrofitting, I believe Subispeed used to sell a kit, which included the signals, the wires with some pre-terminated "terminal connectors" (so you could just plug them into the existing door harness), and paint-matched covers for the mirrors. There also used to be someone on one of the WRX forums (here's the website) that used to sell just the wiring harness (and had part numbers - I can't recall if the WRX numbers are the same as the Forester - they might be). You could do it without the "harness", but it just made things easier.

 

[lepa71]

Does it matter if mine are heated with approach light?

 

[cfodder]

Does it matter if mine are heated with approach light?

Nope. Both my 2016 and 2018 had the heated mirrors and approach light. All that really means is if you do pull the actual mirror lens off, it has two sets of wires on it. Otherwise, it's still just a matter of running the wires down into the door (to the harness) and adding on the actual turn signals. If you do the "wire fish" method down the mirror, the hardest part is pulling off the door panel to get to everything.

 

[2015espy]

Check out my thread for installing Subispeed mirror turn signal lights. Agree with cfodder, take the mirrors of to do the work. Much easier.