Recommanded for Type-S owners with aftermarket decks, especially to those running an aftermarket subwoofer. The BOSE amp bypass will help eliminate your speakers drowning out your subwoofer. I'm not saying the below instructions is the proper way of bypassing the amp, but the easiest I found doing it this way.
Tools needed:
1x Utility Knife
18x Wire Tap in connectors [$2.99 for 7 at Radioshack/Source]
3 feet of 18-22 gauge wire [I took a old computer's power harness and use those wires]
1x Plier
2x Zip Ties
Cost: Under $7 dollars.
Step by Step:
Instead of taking out the seat like some suggest, you can detach the harness from the back of the passenger seat with a pair of small asian hands, then pull the harness out from the front of the seat to work with. If you disconnect the harness for the subwoofer as well, it will give you more length to pull out and work with. I couldn't undo the subwoofer harness, so I just worked with how ever much length i could pull.
Now that the harness is exposed, cut the electrical tape off and pull the black plastic wire hosing about 3 inches and cut it off. This will expose about 4-5 inches of wires to work with, plus afterwards the wires won't be as packed together; therefore, it'll be easier to tap.
Afterwards just follow the instructions below from the bypass guide and tap all 18 wires. You can link the 2 tappers with the 18-22 gauge wire, make sure they're snug afterwards.
Harness Wire Layout:
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13
14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26
Harness Wire Blueprint:
1 | GRY/RED | Passenger's Door Speaker (-), Right tweeter (-)
2 | GRN/YEL | Passenger's Door Speaker (+), Right weeter (+)
3 | BLU/RED | Constant power
4 | ------- | Not Used
5 | BRN | Radio Switch
6 | LT GRN | Rear stereo amplifier - bass signal (+)
7 | RED | Audio unit - Right Rear (-)
8 | GRN | Audio unit - Right Front (-)
9 | BLK | Audio unit - Left Rear (-)
10 | BRN | Audio unit - Left Front (-)
11 | ------- | Not Used
12 | BLU/ WHT | Left Rear Speaker (+)
13 | BLU/BLK | Left Rear Speaker (-)
14 | BLU/YEL | Right Rear Speaker (-)
15 | PNK | Right Rear Speaker (+)
16 | BLK | Ground (G502)
17 | WHT/BLU | Shielding
18 | ------- | Not Used
19 | GRN/WHT | Rear Amplifier - bass signal (-)
20 | YEL | Audio Unit - Right Rear (+)
21 | ORN | Audio unit - Right Front (+)
22 | WHT | Audio unit - Left Rear (+)
23 | BLU | Audio unit - Left Front (+)
24 | ------- | Not Used
25 | LT GRN | Left Tweeter (-) drivers door speaker (-)
26 | GRN/BLK | Driver's Door Speaker (+), Left Tweeter (+)
Wire Tapping Guide
7->14
8->1
9->13
10->25
20->15
21->2
22->12
23->26
Fire up the stereo, use the fade & balance to test if each speaker works after the bypass. I came across some problems where my front passenger and rear driver did not work. But that was due to double tapping a wrong wire, and also the tap in splicer did not cut deep enough through the plastic and into the copper wiring.
If everything works fine, then just zip tie the bundle of wires and tuck it back underneath the seat.
Results
Sweet! The speakers no longer drown out the subwoofer, and volume 1 doesn't sound like volume 10 anymore, and the feedback noise is gone. Sound is now more crisp, but now the speakers will start to distort at about volume 27 on my deck (*May vary on other decks), so maybe a wise choice to upgrade speakers if you want to crank up the stereo louder. Plus, I notice the light start dimming with the bass as volume exceeds over 24. Other than that, it sounds way better than before!
End Notes
Although it took me some troubleshooting to get everything to work, but if all the wires are tapped correctly, it should be done in about 30min or so. I'll post some pictures if you guys have any questions.
I hope this guide helps some of the people here with aftermarket decks still hooked up to their stock typeS BOSE amp. Generally, it's not too bad if you just have a deck, but if you have a subwoofer running, you're best to bypass the BOSE amp so the speakers won't drown out your bass.