daczone
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Add a Subwoofer to your Lightning
(I created this quickly.... Sorry if there are typos, sometimes my hands don't keep up with my brain).
HOW TO:
I bought a 2024 Lightning (March 9th 2025) and quickly realized how bad the B&O system was. This is on a Lariat 8 speaker system (front doors x 2, tweeters x 2, center dash x 1, rear doors x 2, rear subwoofer x 1)
I couldn’t find a lot of information on interfacing to the factory sound system short of spending thousands of dollars for premade cables.
[NOTE: I don't like crimp connectors and I solder EVERYTHING for a solid connection] So if you see something weird... yes it could be done another way.
This is the solution I did:
Kicker KEYLOCK ($130) This is a DSP that provides the line out needed for any amplifier.
Skar Audio RP-1200.1D ($160) 1200 watt digital monoblock. Do not use any old amplifiers you have laying around if they are not class D. Class D amps are more e5icient.
Power Cable, I used DS18 kit ($26) This kit includes 4 gauge power wire as well as RCA, hookup wire for your amp and everything you need.
Skar Audio Dual 12” Subs with speakers for under the rear seat ($340).
Optional: Pac APH-FD02 harness.
This is by no means the only solution. I choose these components based on cost and quality.
POWER
The 12v Power source is the 12v battery. The amp will be mounted in the back and the power is in the front trunk. As bad as that sounds installing the Power Cable was pretty straight forward. I used a piece of solid wire to fish the wire along the drivers side under the door trim. The front and rear door trim pop right out (straight up). That will give you access. I fed the wire from the rear door to the front, and then from the rear door to the back. Why did I choose to do the drivers side when others did the passenger side? The amp is located on the drivers side, the battery you will connect to is in the center of the trunk. Which brings up how do you get through the firewall? I used a audio grommet and drilled a hole.
Installed looks like this:
(ALWAYS INSTALL A FUSE CLOSEST to the power source, not the far end).
Notice the new wire in split loom and the fuse ziptied on the ground wire so it doesn't go anywhere. The wire lug goes on the battery with a 10m nut.
This gave me the straightest path of the wire. The wire was passed through the grommet with a little help from some dish soap. Where the wire comes out under the hood, I put it some protector (slit loom). This was pretty easy, but remember to measure before you drill. I did not drill anywhere. I knew exactly where the wire would come out. I choose a location just to the right of the main harness.
AMP
I used the old SUBWOOFER mount as a AMP rack for the AMP. The RP-1200.1D just happens to be the width of the 6x9 subwoofer. So it fits in that cage. It is thicker (taller) (and longer) so that subwoofer mount
needs to be adjusted. But good news is it’s all plastic. So a some Dremel later it all fit perfectly. I used a thin board (painted black) adhered to the mount for the sub to sit on. It sits at the same angle as the subwoofer. I used the bolt on one of the legs as a ground for the amp (and the ground on the Kicker keylok).
KEYLOC
You could probably use a cheap line out unit for just the Subwooder, BUT the Keyloc provides AMP ON signal for your SUB as well. I mounted the keyloc above the factory amplifier behind the passenger rear seat on the back of the cab. (I 3d printed a mount) there are some factory bolts that just needed 10 mm nuts, So I used those as a place to mount it. The Keyloc can be used with a Pac APH-FD02 cable to provide full range sound as the input, but I simply used the factory subwoofer as a source and it sounds real good. Gave the system what it was missing. (See Wiring for more on the Pac APH-FD02)
BASS KNOB
The Skar 1200.1D comes with a little tiny bass knob in a metal box.
I’ve seen installations where guys put this between the seats, in the center console or even near the light switch on the dash. I wanted this in a location where is was easy to use, and not look like a add on. So I decided to drill a hole below the coin slot.
I changed the knob to a 40mm metal knob and 3d printed a mount. I removed the unit from the metal case. I printed a 3mm washer so that knob can never make contact with the dash (since it is metal)
WIRING
Wiring looks like this. 12V battery provides all of the power. Power is also run to the KICKER KEYLOC. The KEYLOC provides switched power (REM OUT) to the AMP. The Remote In on the KEYLOC is run to along with the R- and R+, L – and L+ to the existing subwoofer output. This provides the signal for the AMP, via the KEYLOC. The KEYLOC also uses that signal to generate a TURN ON feed for itself and the AMP.
APH-FD02
You CAN use the APH-FD02 harness with a few caveats.
Tabs need to be snipped on both the harness side and the AMP factory connector. The labels on the wiring is wrong. Some wires may be removed!
This harness needs to be setup as a pass through. All of the speaker wires are left unterminated. Interestingly the harness as 2 subwoofers feeds for left and right which also matches the factory harness.
(Notice the tweeters and center dash speaker do not go through the rear amp, they feed from the dash)
I cut 6 of the orange wires that are NOT USED on the harness. Do NOT cut the first 2 orange wires (those are CAN BUS).
For Reference here is my factory plug (2024 Larait) which matches the color codes above.
On the APH-FD02
Cut the 6 unused wires on both ends.
What we need to do:
Connect all the wires back together so that they are a pass thru. This will keep your existing system working.
What I am using here are heat shrink solder connectors: slip on a connector, twist your wires together, slide the connector over the wire, apply heat (lighter, candle etc) and the tubing shrinks and the solder melts into the wires.
Keep these out:
For the last 2 (subwoofer wires) keep 1 long
Connect them together leaving 1 end hanging out of the connector (These are the wires that will go to your KEYLOC)
When you are done you will have something like this:
Wrap it with some fabric tape
(Notice the notch snipped o5 the connector to fit our trucks)
And finally some electrical tape. You should now have a pass through cable. The 4 wires hanging out are from pins 5,15 and 20,20
The wires are miss labeled as this PAC adapter is for a di5erent application.
BASIC WIRING DIAGRAM
2 ways to get the source of the audio
Option1: (Factory Subwoofer Bass roll-off)
From the subwoofer feed (use the plug that was plugged into your subwoofer)
It comes o5 the back of the speaker. You wire white to R+, L+ and REMOTE IN. You wire the black wire to R-, L- to the KEYLOC
Option 2: (Factory Bass roll-off fix)
Use the APH-FD02 harness you made.
Connect your 4 wires to the R+,R-,L+,LConnect the remote in to the R+ line as well. This triggers the KEYLOC to turn on.
Extras (3D Prints)
These are all on THINGIVERSE under my name daczone If using the BASS KNOB from SKAR, trim off part of the circuit board.
This will allow the shaft to be longer and go through your dash. I designed this mount to hold the circuit board securely
Knob from Amazon.
Results.... It sounds INCREDIBLE
Reused the Speaker Mount as a AMP Rack (Dremel away!)
Knob going in
I also did a 3d print for block off plate for the factory subwoofer, otherwise you will have a big hole in the back of your truck. also a mount for the keyloc. There are bolts already above the factory amp. My mount allows you to use this area to securely mount the keyloc.
This is the HOLE behind your subwoofer:
(I created this quickly.... Sorry if there are typos, sometimes my hands don't keep up with my brain).
HOW TO:
I bought a 2024 Lightning (March 9th 2025) and quickly realized how bad the B&O system was. This is on a Lariat 8 speaker system (front doors x 2, tweeters x 2, center dash x 1, rear doors x 2, rear subwoofer x 1)
I couldn’t find a lot of information on interfacing to the factory sound system short of spending thousands of dollars for premade cables.
[NOTE: I don't like crimp connectors and I solder EVERYTHING for a solid connection] So if you see something weird... yes it could be done another way.
This is the solution I did:
Kicker KEYLOCK ($130) This is a DSP that provides the line out needed for any amplifier.
Skar Audio RP-1200.1D ($160) 1200 watt digital monoblock. Do not use any old amplifiers you have laying around if they are not class D. Class D amps are more e5icient.
Power Cable, I used DS18 kit ($26) This kit includes 4 gauge power wire as well as RCA, hookup wire for your amp and everything you need.
Skar Audio Dual 12” Subs with speakers for under the rear seat ($340).
Optional: Pac APH-FD02 harness.
This is by no means the only solution. I choose these components based on cost and quality.
POWER
The 12v Power source is the 12v battery. The amp will be mounted in the back and the power is in the front trunk. As bad as that sounds installing the Power Cable was pretty straight forward. I used a piece of solid wire to fish the wire along the drivers side under the door trim. The front and rear door trim pop right out (straight up). That will give you access. I fed the wire from the rear door to the front, and then from the rear door to the back. Why did I choose to do the drivers side when others did the passenger side? The amp is located on the drivers side, the battery you will connect to is in the center of the trunk. Which brings up how do you get through the firewall? I used a audio grommet and drilled a hole.
Installed looks like this:
(ALWAYS INSTALL A FUSE CLOSEST to the power source, not the far end).
Notice the new wire in split loom and the fuse ziptied on the ground wire so it doesn't go anywhere. The wire lug goes on the battery with a 10m nut.
This gave me the straightest path of the wire. The wire was passed through the grommet with a little help from some dish soap. Where the wire comes out under the hood, I put it some protector (slit loom). This was pretty easy, but remember to measure before you drill. I did not drill anywhere. I knew exactly where the wire would come out. I choose a location just to the right of the main harness.
AMP
I used the old SUBWOOFER mount as a AMP rack for the AMP. The RP-1200.1D just happens to be the width of the 6x9 subwoofer. So it fits in that cage. It is thicker (taller) (and longer) so that subwoofer mount
needs to be adjusted. But good news is it’s all plastic. So a some Dremel later it all fit perfectly. I used a thin board (painted black) adhered to the mount for the sub to sit on. It sits at the same angle as the subwoofer. I used the bolt on one of the legs as a ground for the amp (and the ground on the Kicker keylok).
KEYLOC
You could probably use a cheap line out unit for just the Subwooder, BUT the Keyloc provides AMP ON signal for your SUB as well. I mounted the keyloc above the factory amplifier behind the passenger rear seat on the back of the cab. (I 3d printed a mount) there are some factory bolts that just needed 10 mm nuts, So I used those as a place to mount it. The Keyloc can be used with a Pac APH-FD02 cable to provide full range sound as the input, but I simply used the factory subwoofer as a source and it sounds real good. Gave the system what it was missing. (See Wiring for more on the Pac APH-FD02)
BASS KNOB
The Skar 1200.1D comes with a little tiny bass knob in a metal box.
I’ve seen installations where guys put this between the seats, in the center console or even near the light switch on the dash. I wanted this in a location where is was easy to use, and not look like a add on. So I decided to drill a hole below the coin slot.
I changed the knob to a 40mm metal knob and 3d printed a mount. I removed the unit from the metal case. I printed a 3mm washer so that knob can never make contact with the dash (since it is metal)
WIRING
Wiring looks like this. 12V battery provides all of the power. Power is also run to the KICKER KEYLOC. The KEYLOC provides switched power (REM OUT) to the AMP. The Remote In on the KEYLOC is run to along with the R- and R+, L – and L+ to the existing subwoofer output. This provides the signal for the AMP, via the KEYLOC. The KEYLOC also uses that signal to generate a TURN ON feed for itself and the AMP.
APH-FD02
You CAN use the APH-FD02 harness with a few caveats.
Tabs need to be snipped on both the harness side and the AMP factory connector. The labels on the wiring is wrong. Some wires may be removed!
This harness needs to be setup as a pass through. All of the speaker wires are left unterminated. Interestingly the harness as 2 subwoofers feeds for left and right which also matches the factory harness.
(Notice the tweeters and center dash speaker do not go through the rear amp, they feed from the dash)
I cut 6 of the orange wires that are NOT USED on the harness. Do NOT cut the first 2 orange wires (those are CAN BUS).
For Reference here is my factory plug (2024 Larait) which matches the color codes above.
On the APH-FD02
Cut the 6 unused wires on both ends.
What we need to do:
Connect all the wires back together so that they are a pass thru. This will keep your existing system working.
What I am using here are heat shrink solder connectors: slip on a connector, twist your wires together, slide the connector over the wire, apply heat (lighter, candle etc) and the tubing shrinks and the solder melts into the wires.
Keep these out:
For the last 2 (subwoofer wires) keep 1 long
Connect them together leaving 1 end hanging out of the connector (These are the wires that will go to your KEYLOC)
When you are done you will have something like this:
Wrap it with some fabric tape
(Notice the notch snipped o5 the connector to fit our trucks)
And finally some electrical tape. You should now have a pass through cable. The 4 wires hanging out are from pins 5,15 and 20,20
The wires are miss labeled as this PAC adapter is for a di5erent application.
BASIC WIRING DIAGRAM
2 ways to get the source of the audio
Option1: (Factory Subwoofer Bass roll-off)
From the subwoofer feed (use the plug that was plugged into your subwoofer)
It comes o5 the back of the speaker. You wire white to R+, L+ and REMOTE IN. You wire the black wire to R-, L- to the KEYLOC
Option 2: (Factory Bass roll-off fix)
Use the APH-FD02 harness you made.
Connect your 4 wires to the R+,R-,L+,LConnect the remote in to the R+ line as well. This triggers the KEYLOC to turn on.
Extras (3D Prints)
These are all on THINGIVERSE under my name daczone If using the BASS KNOB from SKAR, trim off part of the circuit board.
This will allow the shaft to be longer and go through your dash. I designed this mount to hold the circuit board securely
Knob from Amazon.
Results.... It sounds INCREDIBLE
Reused the Speaker Mount as a AMP Rack (Dremel away!)
Knob going in
I also did a 3d print for block off plate for the factory subwoofer, otherwise you will have a big hole in the back of your truck. also a mount for the keyloc. There are bolts already above the factory amp. My mount allows you to use this area to securely mount the keyloc.
This is the HOLE behind your subwoofer:
Sponsored
Last edited:
