Originally Posted by runninstrong
I have a Clarion DXZ865MP HU and would like to put it into my 07 Legacy, and keep the stock sub operational. All I have to do is hook up the wires from the sub straight to the new harness, and it will be operational? correct? what about the ground, and power on? Thanks.
If you use a wiring adapter ("forward" harness) to install the Clarion, then you can simply plug the sub T-harness between the car's harness and the forward harness, similar to how it's connected with your stock HU now.
You'll need to make one mod to the sub T-harness. See this thread:
stock sub w/ aftermarket hu
post #18 for pictures, and posts 20 & 21 for instructions.
[UPDATE: No mode required. 2007 factory sub T-harness went back to the "old" style -- dropped the square 8-pin connector. T-harness will be plug-n-play.]
The factory sub harness has no power-on wire. See the info in the Stock HU thread.