BMW E46 Subwoofer System by BSW Installation Guide: d110.e46c for BMW 3 Series

We’re going to proceed as follows:
1. Disassembling the trunk
2. Power/ground wire connections
3. Making appropriate wiring connections for audio inputs
4. Installing the subwoofer enclosure
5. Tuning/testing the system

Disassembling the Trunk Panels:
All of our connections take place in the trunk. We need to remove the drivers side carpeted panel in order to gain access to the factory amplifier, where we will tap into the factory audio system.
1. Begin by removing all items from the trunk of the vehicle. Make sure that all tail lights are in working order. If not, now is a good time to replace them. Also remove the carpet that covers the floor of the trunk, as it will reveal several fasteners that will need removing.
2. Start by removing the taillight covers. Push inward on the clip, and the light will release itself. Now depress the wiring clip attached to the light bulb housing to release the housing, and move the housing safely away from your working space
3. Now, look to the floor of the trunk. You will see that the two plastic casings on either side of the trunk are secured by plastic screws on the passenger side and fasteners on the drivers’ side. Remove the fasteners using you panel removal tool as shown. The plastic screws on the passenger side can be removed using a flat head screwdriver and turning them 90 degrees in either direction. The battery is located underneath this panel on the passenger side of the vehicle.
4. Remove these panels and place them to the side. Be sure and keep the fasteners together with their respective panels.
5. Now, look to the driver’s side of the trunk and identify the two black fasteners shown in the photo below. We need to remove these in the same manner as shown above in the photo on the left. Once removed, the panel can be removed and the factory amplifier will be revealed, as shown in the photo on the right. There is also one more fastener on the front edge (closest to the cabin) slightly behind the side bolster. You’ll see where the panel is being held in when you attempt to remove the carpeted panel. Remove this as well, and place it with the other fasteners.

Power/Ground Connections for the new Amplifier:
IMPORTANT: Before you make any connections, disconnect the negative battery terminal from the battery. This will reduce the chance of electrical damage to the vehicle.
- Now that the vehicle is sufficiently disassembled, we can begin making our connections with the included amplifier wiring harness. We’re going to start with the power, ground, and remote turn on connections, and then move on to the Line Output Converter connections (RCA Cable connections)
Power Wire (Large Gauge Red Wire): Route the large red wire to the positive terminal of the battery. Loosen and remove the 10mm nut on top of the terminal that secures the actual terminal to the battery. Put the amplifier power wire ring over the bolt, and tighten the nut back down with the terminal on the battery. This is the primary power supply for your new amplifier. Connect the other side of the power wire to the +12V terminal on the amplifier. ONLY when both sides of the wire are connected should you install the included fuse into the in-line.

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