GS300PDX

Trying to finish up this subwoofer install on a 2014 IS250 but just hit a wall.

When I went to add the LOC, the left and right are opposite when looking at the diagram compared to my harness. The diagram came from a 2015 IS350 Fsport (one that was posted on the forum in 2016), so I'm curious if the wire colors are different for my year.

Would it be smarter to just splice my LOC's +/- and run it off the sub wiring pre-amp?

Anything helps!

Sasnuke

The wiring diagram you posted is the corrected one for 2014 as well and is labelled correctly.
What you don't know is that the pins are labelled based on the connector being disconnected and turned so you are looking at the metal pin side, not the colored wire side...that's how Toyota labels the pins in the wiring diagrams.
Everything is as it should be on the car harness in your pic of the vehicle.

GS300PDX

So basicallly, wire my LOC to the diagrams +/-?
I currently have it wired the correct way, with still no signal to my subwoofer. Are these the correct pin/color combo for the sub on the same harness?

Pin #6 - Sub (+) Grey
Pin #21 - Sub (-) Light Blue

Sasnuke

Those are the correct pins for the sub wires.
Unfortunately I don't know much about aftermarket audio hookups, but I can tell you for sure what's what on the vehicle side.