I can't seem to find the R39 socket in the roof wiring of the 2105

 

I doubt the spoiler would make a difference, assuming your 2015 has the third brake light.

Power lift gate could very well be the difference. Having the power lift gate on my 2017, I believe there are electrics in the latch mechanism that fully close and lock the tailgate. That may be an issue with converting it to a manual gate. (I'm just speculating here.) I know I can close and latch my power gate manually. Again, just guessing, but at worst, you might have to swap the latch mechanism over.

 

Thanks, I will know shortly and post back, just at the point of physically swapping them. It looks like all the wiring for the power lift gate controls go through R39.

My Forester doesn't have the power liftgate but I did take the interior trim from the doner car. I just hope they communicate properly.

 

You would need to install the power lift-gate and a few other things like switches. You would also need 2 different inside trim panels to fit around the lift unit.

You will probably need to change the configuration of the Forester so it can talk with the new Power Rear Gate Control Module, this needs a bi-directional scanner connected to the OBD-2 port to make the changes.

It looks like a lot of work and is just another reason I am glad to have the manual rear gate.

Have fun

 

IIRC the power gate on the SJs was a bit of a problem child. I was glad my old '17 didn't have one.

 

We have the power left gate on our 2018 Limited, and its operation is indeed a bit funky at times. But when it works as intended it's nice to have.

 

Just posting an update. First attempt didn’t go as planned. Physically, everything matches up and bolts on fine. The issue is the latch button — it doesn’t work.

I tried swapping the latch mechanism and harness from my 2015 into the 2016 liftgate, but the 2015 latch assembly doesn’t line up with the 2016 bolt holes. So at this point, everything is back the way it was.

Unless I can figure out how to re-wire the 2016 latch to work with the 2015 harness, I’m stuck.

If anyone has done this and knows the wiring differences (or if there’s a way to adapt the latch), I’d appreciate the guidance.