Be sure to take plenty of pictures
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1st step, remove the subwoofer box. There is a 10mm bolt on the left side of the subwoofer box which needs to be removed. Also remove the spare tire like holder which spins off. Finally disconnect the sub wiring harness. Then simply lift the sub box up and out of the trunk. It is surprising light, the sub woofers weigh only about 2 pounds each. The new subs with much larger magnets weigh in at about 11 pounds each so this upgrade will add 25 pounds to the rear of the car when including the new amp.
10 mm bolt
![Electronics Technology Auto part Electronic device Audio equipment]()
Sub harness
![Technology]()
You can see the round plastic holder which needs to be unscrewed-removed.
![Vehicle Car Automotive exterior Auto part Automotive window part]()
piece of cake, removal could not be any easier.
![Fictional character Vehicle]()
10 mm bolt
Sub harness
You can see the round plastic holder which needs to be unscrewed-removed.
piece of cake, removal could not be any easier.
Next step is to remove the HK subs from the box, create a new sub wiring harness and install the new subs.
There are many ways to wire the subs up. I decided to modify the sub harness and use them as an input into the amplifier. That way I could solder the two plastic connectors back on, an easy modification to put it back to stock. I did not want to splice into the main harness. You can see the grey end attaches to the main harness and the 3 connectors go to the subs. The factory subs are dual voice coil so two connectors go to the left most sub and the other goes to the right sub.
Also notice there is a thick rubber grommet which plugs the wire hole up and passes the wires out of the sub box. I did not want to cut that up so I found a tapered rubber stopper that fit perfectly for the job. There will be more detail in the next post about how I modified the harness etc.
Below is a pic of the factory subs and wiring harness. Amazing how light these subs are, I think if I left the HK subs in the box and just added an amp I could come very close to the improvement I wanted to make. But never bothered to take that approach and went for new subs.
![Auto part]()
Empty sub box, I shaved down the little raised nubs where the factory mounting holes are located so the new subs sit flush.
![Auto part]()
I ran two sets of speaker wire through my new grommet. The thin side will be pushed through the hole in the sub box to pass the wires through
![Wire Technology Cable Electronic device Electrical wiring]()
I soldered a 4 wire auto connector I bough on eBay so I can easily detach the sub box just like stock
![Wire Electrical wiring Cable Technology Electrical supply]()
Added some poly-fill to help dampen the subs
![Audio equipment Electronics]()
Wired up the new subs, they fit perfect from a depth perspective. The only issues is they have 8 holes where the factory has 6 so you have to make additional holes in the sub box. I used #8 3/4” self taping plastic screws and they worked fine. Just be careful not to over tighten them, the plastic in the box is not all that thick and you could strip the holes if you are not careful. I recommend hand tightening them.
Wired up the subs to the new sub harness
![Audio equipment Technology Auto part Electronic device Personal protective equipment]()
Self taping screws
![Screw Fastener Auto part Metal]()
![Material property Font Technology Label Electronic device]()
The new subs are now installed in the box, notice how the new sub wire harness is installed as well. Looks pretty good.
![Car subwoofer Subwoofer Loudspeaker Vehicle audio Audio equipment]()
There are many ways to wire the subs up. I decided to modify the sub harness and use them as an input into the amplifier. That way I could solder the two plastic connectors back on, an easy modification to put it back to stock. I did not want to splice into the main harness. You can see the grey end attaches to the main harness and the 3 connectors go to the subs. The factory subs are dual voice coil so two connectors go to the left most sub and the other goes to the right sub.
Also notice there is a thick rubber grommet which plugs the wire hole up and passes the wires out of the sub box. I did not want to cut that up so I found a tapered rubber stopper that fit perfectly for the job. There will be more detail in the next post about how I modified the harness etc.
Below is a pic of the factory subs and wiring harness. Amazing how light these subs are, I think if I left the HK subs in the box and just added an amp I could come very close to the improvement I wanted to make. But never bothered to take that approach and went for new subs.
Empty sub box, I shaved down the little raised nubs where the factory mounting holes are located so the new subs sit flush.
I ran two sets of speaker wire through my new grommet. The thin side will be pushed through the hole in the sub box to pass the wires through
I soldered a 4 wire auto connector I bough on eBay so I can easily detach the sub box just like stock
Added some poly-fill to help dampen the subs
Wired up the new subs, they fit perfect from a depth perspective. The only issues is they have 8 holes where the factory has 6 so you have to make additional holes in the sub box. I used #8 3/4” self taping plastic screws and they worked fine. Just be careful not to over tighten them, the plastic in the box is not all that thick and you could strip the holes if you are not careful. I recommend hand tightening them.
Wired up the subs to the new sub harness
Self taping screws
The new subs are now installed in the box, notice how the new sub wire harness is installed as well. Looks pretty good.
Thanks for the pics and the info 
The next step was to modify the sub wiring harness. This mod swaps the existing speaker connectors with RCA jacks. So what used to be input wires to the subs are now speaker level inputs to the amp. Also, there is a switch setting that tells the amp the input to the amp is high voltage and when it sees that the speakers have been turned on, it in-turn powers up the amplifier, It works perfectly.
Here is my understanding of the wiring harness, I used some information found in another thread and extended that information from the main harness to the sub harness:
Purpose => Main harness color => sub harness color
Sub 1a positive => Gray/Brown => Solid Green
Sub 1a negative => Green/Orange => Solid White
Sub 1b positive => Gray/White => Solid Red
Sub 1b negative => Green/White => Solid Orange
Sub 2 positive => Gray/Red => Solid Blue
Sub 2 negative => Green/Orange => Solid White
The stock subs are dual voice coil and the driver side sub has both coils wired while the other sub had only one of the coils wired. I chose to use Sub 1a’s wires and Sub 2’s wires as input into the amp. Here are some pics...
Two wires for Sub 1
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Sub 1a wires
![Technology Cable Electronics Electronic device Finger]()
Sub 1b wires
![Light Finger Hand Plastic]()
Sub 2 wires
![Text Finger Material property Hand Technology]()
Subs with the sub harness
![Auto part Table Camera]()
I clipped Sub1a and Sub 2 wire connectors and used those wires as inputs into the Amp. On this amp I had to solder in speaker wire to RCA adapters onto the sub wire harness. Here is a pic of the finished harness.
![Technology Electronic device Cable Wire Linens]()
Here is my understanding of the wiring harness, I used some information found in another thread and extended that information from the main harness to the sub harness:
Purpose => Main harness color => sub harness color
Sub 1a positive => Gray/Brown => Solid Green
Sub 1a negative => Green/Orange => Solid White
Sub 1b positive => Gray/White => Solid Red
Sub 1b negative => Green/White => Solid Orange
Sub 2 positive => Gray/Red => Solid Blue
Sub 2 negative => Green/Orange => Solid White
The stock subs are dual voice coil and the driver side sub has both coils wired while the other sub had only one of the coils wired. I chose to use Sub 1a’s wires and Sub 2’s wires as input into the amp. Here are some pics...
Two wires for Sub 1
Sub 1a wires
Sub 1b wires
Sub 2 wires
Subs with the sub harness
I clipped Sub1a and Sub 2 wire connectors and used those wires as inputs into the Amp. On this amp I had to solder in speaker wire to RCA adapters onto the sub wire harness. Here is a pic of the finished harness.
Time to put it all together....
Installed the sub box with the new JLAudio subs
![Audio equipment Vehicle audio Subwoofer Auto part Technology]()
The amp is all wired up, positive 4 gauge wire(blue) goes from the positive battery terminal to a large fuse(supplied in the amp kit) then into the amp. The 4 gauge ground wire(gray) is connected to the grounding bolt to the right of the battery. When you wire up the Amp disconnect the grounding terminal located on top of the battery to prevent shock.
Here is a pic of the amp installed in the right rear of the trunk. The Amp output wires have been connected to the male end of the new sub wire harness. The RCA amp input wires come from the modified factory sub wire harness. You can see all the adjustment dials and switches on the amp. You can boost the lower bass(I chose +8 dB), change the crossover frequency(I chose 60 HZ) specify how the Amp turns on(I chose to turn on when a low signal is detected).
![Electronics Electronic device Technology]()
As it looks now with the floor panel reinstalled. I’ll probably run the wires through a gray cable flex tube to clean the look up.
![Cable Technology Electronic device Electronics Audio equipment]()
Now that I’ve been listening to the system for a couple weeks I can honestly say I enjoy the sound system very much. I found no need to run a remote sub volume knob. If you want more or less bass you can always use factory equalizer. I just find the overall sound is cleaner/clearer and not muddy. The new sound has clean deep bass.
Hope you enjoyed my build thread!
Installed the sub box with the new JLAudio subs
The amp is all wired up, positive 4 gauge wire(blue) goes from the positive battery terminal to a large fuse(supplied in the amp kit) then into the amp. The 4 gauge ground wire(gray) is connected to the grounding bolt to the right of the battery. When you wire up the Amp disconnect the grounding terminal located on top of the battery to prevent shock.
Here is a pic of the amp installed in the right rear of the trunk. The Amp output wires have been connected to the male end of the new sub wire harness. The RCA amp input wires come from the modified factory sub wire harness. You can see all the adjustment dials and switches on the amp. You can boost the lower bass(I chose +8 dB), change the crossover frequency(I chose 60 HZ) specify how the Amp turns on(I chose to turn on when a low signal is detected).
As it looks now with the floor panel reinstalled. I’ll probably run the wires through a gray cable flex tube to clean the look up.
Now that I’ve been listening to the system for a couple weeks I can honestly say I enjoy the sound system very much. I found no need to run a remote sub volume knob. If you want more or less bass you can always use factory equalizer. I just find the overall sound is cleaner/clearer and not muddy. The new sound has clean deep bass.
Hope you enjoyed my build thread!
Attachments
I mounted it to a board under the carpet. Screwed the amp into the board. Here are a few more pics.
I cut up a thin piece of plywood...
I had some Velcro lying around and used the fuzzy side so it did not rattle against the metal surface under the carpeting....
Slipped it under the carpet...
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