2003-2009 4Runner Kicker Plug and Play 5-Channel Amplifier and Subwoofer Kit Installation Guide

Welcome to the installation guide for your 2003-2009 4Runner Kicker Plug and Play 5-Channel Amplifier and Subwoofer Kit from Trail Grid Pro! This step-by-step guide is designed to make the installation process as smooth as possible, whether you're a seasoned DIYer or tackling your first audio upgrade.

This installation guide is intended to assist you in installing the following 2003-2009 4Runner amplifier and amplifier/subwoofer bundles:

In this guide, you’ll find:

📢 Important Updates: The written guide includes the latest updates and adjustments that may not be shown in the video, ensuring you have the most up-to-date instructions for a flawless installation.
🎥 Installation Videos: Visual instructions to help you through the process, including a detailed microphone install.
🛠️ Parts Included and Tools Needed: A quick list of everything you'll need to get started.
📝Step-by-Step Instructions: Clear, easy-to-follow directions from disassembling your dash to installing your new Kicker Amplifier.
⚠️ Special Notes: Important information and considerations for your installation.
🛠️ Common Troubleshooting Solutions: Quick and effective fixes for common installation and performance issues.

Important Updates
Installation Video
Tools Needed
Step 1: Disassembling the Dash
Step 2: Removing the Passenger Seat
Step 3: Routing the Power Wire
Step 4: Routing the Main Harness
Step 5: Making Connections to Your Head Unit
Step 6: Reinstall Your Head Unit
Step 7: Connecting the Ground Wire
Step 8: Connecting the Bass Control Knob
Step 9: Mounting the Amplifier to the Mounting Bracket
Step 10: Making Connections to the Amplifier
Step 11: Routing the Subwoofer Wire
Step 12: Connect Power to the Battery
Step 13: Test the System
Step 14: Tune the Amplifier
Step 15: Reassembly

🛠️Parts Included:

Kicker 46CXA6605T 5 Channel Amplifier
AudX 4Runner Amplifier Mounting Bracket
AudX T-Harness
AudX Main harness
RCA adapters
Kicker 47VK6 Amplifier Install Kit
10 Zip Ties
10mm Ground Bolt

🛠️Tools Needed:

Panel removal tool
10mm socket
12mm socket
14mm socket
Ratchet wrench
Socket extension
Phillips head screwdriver
Zip ties
Razor knife
Wire fish

📝Step-by-Step Instructions

Step 1: Disassembling the Dash

Pull up the shifter trim and the storage cubby.
Remove the Phillips screw hidden behind the cubby.
Gently lift off the center console trim.
Pull out the HVAC controls and unplug the connector.
Remove the four factory 10mm bolts under the radio.
Remove the lower knee panel under the steering column (two 10mm bolts).
Gently pull the trim around the radio, disconnecting any switch plugs.
Slide the head unit out and unplug all connectors from the back.

Step 2: Removing the Passenger Seat:

Before running your wiring, you’ll need to remove the front passenger seat to make room for the amplifier and harness routing. Follow these steps carefully:

Remove the Trim Panels
- Lift up the passenger door sill plate (it pops straight up).
- Unscrew and remove the small plastic nut holding the kick panel in place.
- Pull the kick panel straight out to release the clips and set it aside.
Remove the Front Seat Bolts
- Pop off the plastic covers over the front seat bolt brackets.
- Use a 14mm socket to remove both front seat bolts.
Remove the Rear Seat Bolts
- Slide the seat forward to reach the rear bolts.
- Remove the plastic covers on the rear brackets.
- Use a 14mm socket to remove both rear seat bolts.
Access the Seat Wiring
- Move the seat to the middle position and gently tilt it back.
- Locate the wiring connectors under the seat.
- Press the release tabs and disconnect each plug carefully.
Remove the Seat from the Vehicle
- Once all connectors are unplugged, carefully lift the seat out of the vehicle.
- Be mindful of the seat tracks and door frame to avoid scratches.

💡 Pro Tip: Have a towel or blanket ready to set the seat on to prevent any damage to your interior or the seat itself.

Step 3: Routing the Power Wire

Prepare the Power Wire
- Open the hood and secure it.
- Find the power wire with the inline fuse from your install kit.
- Use a 3mm Allen key to connect the short power wire to one side of the fuse holder.
- Connect one end of the long power wire to the other side of the fuse holder the same way.
  - 💡 Tip: Make sure the wire ferrules are tight and secure—this prevents poor connections later.
Route the Power Wire Through the Engine Bay
- Position the ring terminal end near the positive battery terminal, but do not connect it yet.
- Route the power wire neatly along the driver-side fender, across the firewall, and toward the passenger-side firewall grommet (a rubber plug where other wires go into the cabin).
Pass the Wire through the Firewall
- Use a utility knife to carefully cut an "X" in the firewall grommet.
- Push the power wire through the hole into the cab.
  ⚠️ Important: Many Toyota firewall grommets have 2 layers - an outer and inner membrane. Be sure to cut through both..
  ⚠️ Caution: Be careful not to damage any vehicle wiring while cutting.
- Use a wire fish tool if needed to guide the wire through.
- Once it's inside, pull the slack into the passenger-side floorboard.
Route the Power Wire to the Amplifier
- Run the wire along the passenger-side kick panel and through the factory wire channel under the carpet.
- Continue routing it to the amplifier's power connection point under the passenger seat.
- Use the included zip ties to secure any loose wire in the engine bay for a clean, factory-style look.

Step 4: Routing the Main Harness

Position the Main Harness
- Place the main harness under the front passenger seat - this is where the amplifier will mount.
- Identify the T-Harness end (the side that connects to the head unit).
Route the Harness Toward the Dash
- Start routing the T-Harness end forward, under the carpet, toward the center console area.
- Keep the harness low and tucked along the transmission tunnel as you move toward the dash.
- Continue guiding it up toward the gear shifter area - this path keeps it hidden and secure.
  - 💡 Tip: Gently lift the carpet edges and use a plastic panel tool to help tuck the harness underneath without damaging trim pieces.
Bring the Harness Up to the Radio
- With the radio removed, locate the open space behind the dash where your factory connectors plug in.
- Feed the T-Harness connectors up through the dash toward these radio connection points.
- Make sure the harness is free of sharp edges and has enough slack for easy plug-in during the next step.

Step 5: Making Connections to Your Head Unit

Factory Head Unit:

Carefully pull the head unit forward to access the connectors on the back.
Unplug the 10-pin and 6-pin connectors from the rear of the head unit.
Plug the male ends of the AudX T-Harness into the matching 10-pin and 6-pin ports on the head unit.
Connect your vehicle's factory plugs to the female ends of the T-Harness.
- ⚠️ Optional: If you prefer to ground the harness, attach the small black wire ring terminal to a clean, bare metal surface using an existing bolt or screw.

Aftermarket Head Unit:

Disconnect the 10-pin and 6-pin connectors from the rear of the head unit.
Plug the male ends of the AudX T-Harness into those same 10-pin and 6-pin ports.
Connect your vehicle’s factory plugs to the female ends of the T-Harness.
Using the supplied RCA cables, connect the color-coded RCA plugs from your head unit to the corresponding RCA connectors on the harness:
- Front Speakers:
  - White → White
  - Grey → Red
- Rear Speakers:
  - Green → White
  - Purple → Red
- Subwoofer:
  - Orange → White
  - Brown → Red
⚠️ Optional: If you prefer to ground the harness, attach the small black wire ring terminal to a clean, bare metal surface using an existing bolt or screw.

Step 6: Reinstall Your Head Unit

Reconnect All Wiring:
- Double-check that every connector you unplugged earlier is securely re-attached - this includes HVAC plugs, switch connectors, and your new T-Harness connections.
- Make sure no wires are being pinched or twisted behind the dash.
Reposition the Head Unit
- Gently slide the head unit back into the dash opening.
- Line up the mounting holes and reinstall the four factory 10mm bolts to hold it in place.
- Snug them down evenly, but don't overtighten.

⚠️ Important: Don’t reinstall the dash panels or trim pieces yet. You’ll need to test the system first to make sure everything powers on and plays correctly before final reassembly.

Step 7: Connecting the Ground Wire

Locate the Ground Point
- Under the front passenger seat area, look for the factory ground location - this is usually a bare metal spot or existing bolt attached to the vehicle's frame.
Secure the Ground Wire
- Take the provided ground wire from your kit and attach the ring terminal to the factory ground bolt.
- Tighten the bolt snugly to ensure a solid connection.
If No Factory Ground Is Present
- Use the included ground bolt to secure the ring terminal into the pre-threaded hole under the seat.
- Make sure the contact surface is clean, bare metal - paint or coatings can prevent a proper ground.
  - 💡 Pro Tip: A good ground should be short, tight, and connected directly to bare metal. Poor grounding can cause static or amplifier shut-off issues.

Step 8: Connecting the Bass Control Knob

Mount the Bass Knob
- Choose your preferred mounting location - some popular spots include the center console, lower dash panel, or a factory switch blank.
- Use the included Velcro to attach the knob
Connect the Control Wire
- Find the control knob wire coming from your main harness.
- Plug the 3.5mm headphone-style jack into the bass knob until it clicks into place.
Tidy Up the Wiring
- Route the wire neatly along existing factory wiring or trim edges.
- Use zip ties to secure any extra length or loose sections so nothing dangles or gets pinched.

Step 9: Mount Amplifier to the Mounting Bracket

Position the Mounting Bracket
- Place the amplifier mounting bracket on a flat surface with the AudX label facing up.
- Make sure the bracket is oriented the same way it will sit under the passenger seat.
Align the Amplifier
- Set the amplifier on top of the bracket, lining up the pre-drilled holes.
- The RCA ports should face the passenger door - this ensures easier access for wiring.
Secure the Amplifier
- Insert a bolt up through the bottom of the bracket and through the amplifier's mounting hole.
- Add a flat washer, then a split washer, and finally secure it with a nut.
- Use a 9/32" wrench and a Phillips head screwdriver to tighten the hardware.
  - ⚠️ Important: Tighten the bolts snugly, but do not over-tighten—you don’t want to crack the amplifier’s housing or damage the bracket threads.

Step 10: Making Connections To Amplifier

Install the Ground for the RCA Input Harness
- Use a T10 Torx driver to remove one screw from the amplifier's control faceplate.
- Place the ring terminal from the ground wire over the screw hole.
- Reinstall and tighten the screw to secure the ground wire.
Connect the RCA Input Harness
- Plug the RCA harness into the 14-pin connector on the main harness.
- Match and plug in the RCA connectors to the amplifier as follows:
  - Amp 1 (Front Channels):
    - Left = White (FL RCA)
    - Right = Grey (FR RCA)
  - Amp 2 (Rear Channels):
    - Left = Green (RL RCA)
    - Right = Purple (RR RCA)
  - Subwoofer:
    - Left = Orange (SL RCA)
    - Right = Brown (SR RCA)

Connect the Remote Wire:
- Insert the remote wire ferrule into the REM input on the amplifier.
- Tighten the screw with a 3mm Allen wrench.
- Plug the other end into the 4-pin connector on the main harness.
Connect the Wire Fork Harness:
- Connect the Wire Fork Harness to the 8-pin connector on the main harness.
- Match the speaker wires as labeled below:
  - Rear Speakers (Bottom Row):
    - Amp 2 Left + = Green
    - Amp 2 Left - = Green/Black Stripe
    - Amp 2 Right + = Purple
    - Amp 2 Right - = Purple/Black Stripe
  - Front Speakers (Top Row):
    - Amp 1 Left + = White
    - Amp 1 Left - = White/Black Stripe
    - Amp 1 Right + = Grey
    - Amp 1 Right - = Grey/Black Stripe
Connect the Subwoofer Wires
- Connect the ferrule ends of the subwoofer wires to the amplifier terminals:
  - Sub - = Black wire
  - Sub + = Yellow wire
Connect Ground and Power to the Amplifier:
- Attach the provided black ground wire to the amplifier's ground terminal and tighten with a 3mm Allen wrench.
- Connect the power wire to the amplifier's power terminal and tighten using the same 3mm Allen wrench.

Step 11: Routing the Subwoofer Wire

Route the Wire to the Rear of the Vehicle
- Start at the passenger-side kick panel where the subwoofer wire exits the amplifier harness.
- Gently pull up on the rear door sill trim—it will pop straight up to release.
- Route the subwoofer wire through the factory wire channel that runs along the bottom edge of the vehicle interior.
- Continue tucking the wire under the interior plastic panels, following the existing wiring path toward the rear cargo area.
Connect to the Subwoofer
- Once the wire reaches your subwoofer location, strip back a small section of insulation if needed.
- Connect the yellow wire to the positive (+) terminal on your subwoofer.
- Connect the black wire to the negative (–) terminal on your subwoofer.
- Make sure both connections are snug and secure.

Step 12: Connect Power To Battery

Prepare for the Connection
- Make sure your vehicle is turned off and the keys are removed from the ignition.
- Double-check that your inline fuse near the battery is not yet installed—you’ll add it after confirming all connections are secure.
Connect the Power Wire
- Locate the short length of power wire with the pre-installed ring terminal from your kit.
- Attach the ring terminal to the positive (+) battery terminal post.
- Tighten the terminal nut securely to ensure a solid connection.
- Once all connections are verified, install the fuse into the inline fuse holder.

Step 13: Test System

Power On the System
- Turn the key to the ON position or start your vehicle.
- Power on the head unit and play some audio.
- Check that the amplifier powers on—you should see a small indicator light.
- Confirm that sound is coming from all speakers and that the subwoofer is producing bass.
Verify Everything is Working
- Listen for clean, balanced sound across all channels.
- If something doesn't seem right, check all connections - especially the remote turn-on wire and the RCA inputs.

🛠️Troubleshooting Tip:
If your head unit powers on but you don’t hear sound, double-check that the remote turn-on wire is securely connected to the amplifier’s REM input. This wire tells the amp when to power up.

Step 14: Tune The Amplifier

Set Initial Amplifier Settings:
- On your Kicker CXA660.5T amplifier, set the following:
  - Fader: ON
  - Input Level: LO
  - Sub Input: SUB
Adjust Gain Levels:
- Choose a song that plays continuously for a few minutes.
- Turn the volume on your head unit to about 75% of the maximum volume.
- Using a small flathead screwdriver, adjust the Amp 1 gain (Front Speakers) to your desired sound level.
- Repeat the process for the Amp 2 gain (Rear Speakers).
- Adjust the Sub gain last to set your desired bass level.
  - ⚠️ Warning: If you hear distortion, clipping, or audio cutting out, the gain is set too high—reduce accordingly.
Final Adjustments:
- Use your head unit’s built-in EQ settings to fine-tune the overall sound to your personal preference.

Step 15: Reassembly

Reinstall the Seat and Mounting Bracket
- Once you’ve confirmed the system is functioning properly and your amplifier gains are set, begin reassembly.
- Line up the mounting holes on the amplifier mounting bracket with the rear seat bolt holes.
- Place the passenger seat back into position, aligning the rear seat mounts with the amplifier bracket.
- Start all four 14mm seat bolts by hand, then tighten them using a 14mm socket.
- When installed correctly, the amplifier bracket should be sandwiched between the seat mounts and the floor, with the bolts running through the bracket tabs.
Finish Reassembling the Vehicle
- Reinstall all remaining components, including the rest of the seat, center console, and dash panels.