Originally Posted by ericthibeault
I just received my H630SAJ000 [OEM sub for 2010-2011 Legacy/Outback] ... I just can't find any info about this 2010+ OEM sub which has 5 wires, not 6.
I thought I had to connect my RCA L/R sub outputs, ground and constant 12v but that's 6 wires and the sub harness only has 5 wires...
Most of Subaru's OEM rectangular-shaped under-seat subs in the last ~10 years tap the HU's front speaker outputs.
However, the 2010-2011 Legacy/Outback HU models PE645U1 and PE605U6 have a line-level sub output on pins on the 24-pin aux socket.
The H630SAJ000 subs for those Legacy/Outback models use that sub out instead of tapping speaker outputs.
At the 8-pin subwoofer plug, power and ground are on the same pins as with the Impreza, Forester, and older Legacy/Outback subs -- pin 7 = +12 Battery/constant, pin 8 = Ground.
Pin 6 is amp remote turn-on. That has actually been present on the older subs, but never used (since they activate by detecting sound on one of their audio inputs). The H630SAJ000's T-harness connects this to pin 23 on the HU's aux socket.
Pin 2 is the line-level audio +, and pin 5 is the audio ground/shield. The H630SAJ000's T-harness connects these to pins 12 (signal) and 11 and 24 (ground/shield) on the HU's aux socket.
The T-harness passes through many of the other pins on the 24-pin socket. Only 4 pins are used for the aux input (7, 8, 9, 19). I'm not sure why the harness passes through the other pins -- perhaps the HU has some undocumented signals on other pins. The PC board inside the PE605U6 or PE645U1 might give some clues.
For anyone whose Legacy/Outback has that OEM sub and wants to switch to an aftermarket HU, I can make an aux adapter with an extra RCA plug and amp turn-on lead to connect the sub to the new HU's line-level subwoofer output.
If you don't already have that sub, I recommend going with an aftermarket sub instead.