Added an amp/sub to my stock headunit, 2005 STI
Posted: Sat May 21, 2005 3:01 pm
Overall this was not difficult, but because the '05 reverse harness has not yet been released by Metra, finding the equivalent was a challenge.
Basically I wanted to add an Alpine MRV-F450 5 channel amp with a 10" sub to my stock head unit, just until I find a head unit that I can't resist. And I wanted to do all this without cutting my factory harness.
The forward factory harness (80-8901) by metra was missing the orange/white wire for the dimmer (negative) so I had to add one to it. This provides power for the back-lit radio buttons when the headlights are in the "on" position.
No one seems to make, or has in stock a reverse factory harness for the subaru so I used one from a hyundai accent. The only difference is that the wire colors are not the same.
I used a "pac oem II" converter and ran all the wires through it on the "input" side to the reverse harness. The only one I had to run around the converter was the neg. illumination wire (dimmer) because the converter does not have a pass thru wire for this feature.
On the output side of the converter, I connected all but the speaker wires to the forward harness. I then connected my speaker wires from the forward harness to a 12' S16 OEM monster standard cable (4 pair w/ remote wire) and ran it back to the amp which I mounted on the trunk/back-seat wall.
Ran power, ground and amp switch wire to the amp and now my auto dim rear view mirror vibrates like this big flashlight I found in my girlfriends nightstand.
Good luck!
Basically I wanted to add an Alpine MRV-F450 5 channel amp with a 10" sub to my stock head unit, just until I find a head unit that I can't resist. And I wanted to do all this without cutting my factory harness.
The forward factory harness (80-8901) by metra was missing the orange/white wire for the dimmer (negative) so I had to add one to it. This provides power for the back-lit radio buttons when the headlights are in the "on" position.
No one seems to make, or has in stock a reverse factory harness for the subaru so I used one from a hyundai accent. The only difference is that the wire colors are not the same.
I used a "pac oem II" converter and ran all the wires through it on the "input" side to the reverse harness. The only one I had to run around the converter was the neg. illumination wire (dimmer) because the converter does not have a pass thru wire for this feature.
On the output side of the converter, I connected all but the speaker wires to the forward harness. I then connected my speaker wires from the forward harness to a 12' S16 OEM monster standard cable (4 pair w/ remote wire) and ran it back to the amp which I mounted on the trunk/back-seat wall.
Ran power, ground and amp switch wire to the amp and now my auto dim rear view mirror vibrates like this big flashlight I found in my girlfriends nightstand.
Good luck!
I've been thinking of adding a Pheonix Gold 5.1 Amp to it, but have been too engrossed with other mods 
now that it's warm out I've been busy doing other mods, but the speakers will be going in soon. this weekend I have other plans, but I don't want to jinx myself so I'll leave it at that for now...