My truck has the 7 speaker factory Bose sound system with the factory amp and subwoofer in the center console.
I added a single 10" MTX 400 watt subwoofer behind my crew cab rear seat and used my existing 400 watt Kenwood amp to power the sub. I wanted to do an install that was cheap and easy, yet delivered much better sounds response on the low sounds.
Use the links below for two separate ways to add a subwoofer to your factory Bose system.
Setup using PAC OEM-24 adapter (Current Install)
Setup using line level converter (Original Install)
PAC AOEM-GM24 Adapter Setup
I ordered the PAC adapter from someone on ebay, although a number of vendors carry them. Price ranges from $40 to $75. If you put a new head end unit in, get one that has sub-preamp outputs. Then you will not need this PAC adatper. *You ideally would buy a different adapter that interfaces with the steering wheel controls, etc.
I had to pop off the dash cover to access the radio. I removed the 4 screws that hold the radio in and popped the radio out. I followed the directions that came with the PAC adapter to hook it up. I hooked the RCAs to the REAR outputs of the PAC adapter. I then ran two RCA cables down the center console under the passenger seat and to the amp mounted behind the rear crew-cab seat. I opted to not run a control wire for the amp as I had it previously hooked up, however, the PAC adapter does provide an AMP power control wire.
I then hooked the RCAs to my amp and configured my amp to bridge the output to my 10" sub.
The range and clarity of bass seems to be better than what was coming out of the line level converter from my original install.
Jump to photos of single 10" setup.
Line Level Converter Setup
I originally did the sub add using these steps below.
I initially tried to hook a line level converter to the output to the RR and LR speakers, however, I found that they received limited low subwoofer frequencies since the factory Bose amp has a built in cross over that sends the lows to the factory sub. I then tried to take the center console out so I could trace down the wires to the factory subwoofer, I found this to be quite a chore, so I instead started to randomly snip wires coming out of the amp, all that got me was having to solder and tape a lot of wires.
I wasn't about to let myself be beat, so I spent another hour finding all the screws, removing trim, moving seats forward and backwards to get to screws, to get the center console out. Once I got it out, I found that there are four wires feeding the factory sub. I followed the wires back to the amp and found that they went into what I originally thought was a power and control IN side of the amp. I went ahead and took pictures of the sub and wiring harness while I had it out. (see below)
I put the center console all back together and spliced my line level output converter that I got at Wal-Mart for $17.77 to give me RCA outs to my subwoofer amp. Since I only have one sub, I did a mono setup. So I spliced my converter into the Blue White/ Green Black set of sub wires. I ran my RCA cable under the passengers seat, underneath the door trim, to my amp behind the back seat. I ran my 12v amp feedwire underneath the moldings on the drivers side and ran it through the firewall using the same hole that the accelerator wires run through and terminated into the red box that the alternator wire is connected to.
Since I was not able to find a amp power control wire in the center console (I didn't feel like cutting anymore wires), I simply hooked it up to the same fuse I have my radar detector on, that comes on when I have the truck on. I am not concerned with whether the amp is on or off when the radio is not on. I grounded my amp using to the frame of the back seat.
I spent $35 for the box from www.cmttrading.com (They were the only ones to have one that would fit snugly without any major modification) $18 at wal-mart for the line-level converter to RCA. I already had the amp. I would supposed someone could add a simple sub setup for about $100, probably add a 6" bazooka powered tube easily. (They are cheap on ebay.)
So, if you want to add a sub to your factory Bose system that already has a subwoofer, the easiest way to do it is as follows.
Open your center console and remove 9 screws that hold it in. (Four are at the bottom underneath the rubber matte). Then open the cup holder for the back and remove 4 screws from there and the 2 screws at the top. You should now be able to remove the cupholder and have access to the amp wires as seen in Photo C. You can use either set of subwoofer feedwires. (BlueWhite/GreenBlack or Teal/LTBLue) They are found in the RIGHT wiring harness to the amp. The orange wire in this harness appears to always be on. This is the wiring harness that has the least number of wires.)
Hope this helps you. I am by no means an expert on this and am not responsible for anything you do to your truck. This information is provided as-is and could void your audio system warranty.
Questions or comments can be emailed to:
Original Photos - Single 10" sub.
I had to bend this bracket to allow my sub to fit behind the rear seat.
Photos of the center console removed. In the second and third photo you can see the factory sub.
Since I am only running one sub in mono, I only spliced into one
set of wires. The second pair is visible in this photo.
Note: The orange wire nuts are from the RR speaker that I first hooked my sub to. The wires that power the factory Bose sub are on the right of the picture. Picture one shows my connection. (Blue White/ Green Black)
Here is what it looks like all finished with the cheap Wal-Mart line level converter