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Adding a Sub and Amp to the Bose System

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Adding a Sub and Amp to the Bose System

Old 07-21-2006, 01:56 PM
Thread Starter
Join Date: Dec 2004
Location: Seattle, WA
Posts: 8,980
Default Adding a Sub and Amp to the Bose System

Ok it wouldnt fit in the title but we can all thank Bentframe for this writeup

Adding a Sub and Amp to the Factory Bose System:
Time: 1.5-3 hours
Difficulty (1-10): 3

- Amp
- Amplifier power kit
- Subwoofer
- Sub box
- 12-14 gauge subwoofer wire (8 feet). Standard speaker wire works, Monster Cable subwoofer wire works better.
- One set of RCA cables (3-6 feet, depending on where you mount your amp)
- Ground loop isolator
- Five small wire taps (GET EXTRAS!)
- Five male electrical spade connectors (GET EXTRAS!)

- Allen wrench set
- Ratchet
- 8mm socket
- Socket extension (at least 4”)
- Wire cutter/stripper/crimper (usually all found on one tool)
- Drill (don’t be scared, it’s only used to secure the amp)
- Wire coat hanger (high tech, I know)

1. We start with the hard part, running the power wire from the battery to the trunk. Before you start, get your wiper arms up so they’re vertical. Next, remove the cover on your ECU box (black box under the hood right in front of the steering wheel). There are five 8mm bolts to remove. The first four are easy, the last is a little tricky. The fifth bolt is on the rear side of the ECU box, this is the one you will need the extension for. First remove the small metal clip that holds the lower windshield trim in place. Then lift up the trim piece enough to stick your socket down there. (See Figure 1). Remove the bolt slowly, being careful not to drop it. While you've got the cover off, it's a good idea to cut out a small notch in the box for the power cable to go (See Figure 2).
Figure 1:

Figure 2:

2. Next, inside the cab, you’ll need to remove the driver side knee bolster. There are four more 8mm bolts to get that piece out. Two are on the front, underneath caps (See Figure 3), one is down at the bottom right corner of the bolster, just above the gas pedal (See Figure 4), and the fourth is on the side, just below the fuses (See Figure 5).
Figure 3:

Figure 4:

Figure 5:

3. Once the four bolts are removed, pull the knee bolster towards you to slide it out.

4. Now take your coat hanger, straighten it out, and feed it through the small hole in the bottom corner of the ECU box (See Figure 6). Tape the end of your power wire to the end of the coat hanger and pull it back through.
Figure 6:

5. Run the power wire underneath the driver side door jam. To get the wire started, you’ll have to remove the door sill trim. There are two Phillips screws to remove, one is covered by a cap (See Figure 7 & 8 ). Once you get the wire started under the door sill trim, just tuck it under until you get to the back.
Figure 7:

Figure 8:

6. When you get to the back seat area, you’ll have to pop out the trim piece shown in Figure 9 by pulling up.
Figure 9:

7. Remove your rear seat. This is done by simply pulling up and out on the front of the seat.

8. Feed the wire up under the seat and then behind the seat back. This is easier if you fold down the back section first.

9. The next step is to mount your amp. I used the smaller of the two seatbacks, because it was closer to the stock amp and would require less wire. Be careful not to mount the amp too low on the seatback. When you fold the seat back up you’ll need a good 6-8” below the amp for clearance.

10. Cut off the end of one of the RCA cables. Each RCA cable has four wires running through it, two positive and two negative. The outer shield on the RCA ends is the negative, while the inner post is positive.

11. Use the diagram below to see which wires coming off of your stock amp to tap into. Connect the wire taps to the appropriate wires. The ground wire will need to be tapped twice.

12. Crimp your male spade connectors onto the ends of the RCA wires you cut, and onto one end of your remote turn-on wire.

13. Connect the power wire to the amp, then the battery. Connect the ground wire to any piece of bare metal. I used a bolt underneath the rear seat. Plug the RCAs in. Connect your remote turn on wire. Enjoy the bass.

14. Since Audi uses a ‘common ground’ for all the speakers, you will probably run into a ground loop problem. You’ll know because you can hear a horrible screaming sound (your alternator) through your speakers. If this happens, throw a ground loop isolator inline with the RCAs, this should take care of the problem.
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