2007 M35 Subwoofer Installation.
*Disclaimer* - I am not liable for anything you do to your car. This is just a basic walkthrough. If you have never done an audio install, I wouldn't practice on the M.
Task: Subwoofer Installation
Time: A couple hours (took me a little longer, as it was night time and I didnt have the correct info!)
Tools/Supplies Needed: Flathead screwdriver (to remove clips holding trunk liners and engine cover panels)
10mm & 12mm socket (to remove battery and connect power wire)
Line output converter
Amplifier, Subwoofer(s), and Subwoofer enclosure (DUH!)
3M Scotchlok connectors (Wal-mart has them. You can use the blue or reds. I bought a little kit that had both. (Sold where the fuses and stuff are.)
Amp hook-up kit (I got a 6ga Scoshe from wal mart)
The first thing I did was remove every panel/liner from the trunk. They are held on by black clips. Take the flathead and "pop" out the center of the clip. Then the whole clip will pop off. Looks like this stripped:
Next take out the battery. Start by taking off passenger side engine panels. You need to take off the piece attached to the window too. Everything is held on by the same clips as the trunk liner. Use 10 mm socket to remove battery holder. Disconnect battery wires (10mm) and pull out battery.
Next remove the panels on the bottom of both passenger doors. They just pop off.
Take the glovebox off. This is easy, but I didnt really take any pics. Open it, and pull the left side out right. The peg thing holding it in will come out. Kinda twist it and it will come out. Note the sting attached on the right side (its what makes it come down slow. It just pops off. Pop it off
Now its time to run the battery wire. I ran it from the back to the front. Most people would run it front front to back. I think my kit came with 16' of wire so I had more than enough. I will describe how to run it back to front since thats the way I did it.
I started at the rear passenger seat. Pull it back and shove the wire through this hole:
Next, run the wire up towards the front :
Through the door pillar :
Up to front firewall :
I went through the cabin filter area to get to engine bay. I drilled a hole just big enough for the wire to come through. Then, from the engine bay, I stuck a coat hanger through the hole. I taped the wire to it in the car and pulled it through.
Now its time to tap the sub wires. Its real easy. Unplug the connector from the factory sub, and tap into both lines with the 3m connectors
Now, tap the remote wire from the factory amp. Its on the white harness, and the wire is SOLID BROWN. Its the only brown one in the white connector. :
Now run the ground:
Now your basically done. Hook the speaker wire coming from the factory sub you just tapped to the line output converter. You only need to use one set of wires. Hook the rca's to the amp. Hook the power, ground, and remote to the amp. Hook the battery cable in the engine bay to the fuse block, then to the battery. Test it. I adjusted the gain on the LOC and the amp with the bass turned down on the head unit, that way I can turin it up from the HU. If it works, button everything back up and youre done!!!!! #WINNING!!!
Im sorry if this write up sucks, lol. Its my first. But I think you should be able to do it pretty easily from this. Let me know if you have any questions, Im not going anywhere.