Alpine 4 Channel Amplifier and Powered Subwoofer Installation Guide | 2016-2023 Tacoma

Installation Video

Alpine Installation Guide

Parts Included:

• Amplifier assembly:
• Vehicle specific mounting bracket
• Alpine PWE-S8 powered subwoofer
• Alpine KTP-445U 4 channel amplifier
• T-Harness
• Main harness
• RCA adapters
• Power Cable
• 10 Zip Ties
• 10mm Ground Bolt
• Female and male bullet connector

Tools Needed:

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

Step 1

Disassembling the dash and removing the factory radio:

• Remove the outer dash trim by pulling straight back towards you.
• Loosen the four 10mm bolts that hold in the radio bracket.

Step 2

Disassembling your Tacoma:

• Remove the driver side door sill by pulling straight up. 
• Remove the driver side kick panel:
• Remove the button retaining by twisting counter clockwise.
• Pull the kick panel to remove.
• Remove the driver side rear door sill by pulling straight up.
• Remove the driver side lower seat belt screw cover on the B-pillar.
• Remove the 14 mm bolt securing the lower seat belt mount.
• Pull back the weather seal on both sides of the B-pillar.
• Use a panel tool to release the B-pillar cover to remove it.
• Remove the rear seat headrest on the driver side.
• Flip the driver side rear seat down and remove the two screw covers on the lower part of the seat. 
• Use a 14 mm socket to remove the two mounting bolts from the lower part of the seat.
• Remove the seat back and set to the side.
• Use a 12 mm socket to remove the two bolts on the bracket next to the C-pillar and remove the bracket. 
• Remove the rear storage pocket:
• Use a 10 mm socket to remove the two or three bolts from the plastic compartment.
• Remove the plastic compartment.
• Pull back the weather seal from the C-pillar
• Gently pull out on the C-pillar cover to remove.

Step 3

Routing the power wire:

• Provided in the kit is a spyder wrapped power wire with inline fuse.
• Open and secure the hood.
• Start with the ring terminal near the positive battery terminal.
• Route the power wire along the drivers side fender, towards the firewall and towards the driver side firewall grommet.

• Locate a spot to cut an "X" in the grommet using a utility knife. Keep in mind that many Toyota firewall grommets have an exterior and interior membrane that you will need to cut through. Take extra care to not damage any other vehicle wiring when cutting your "X."
• You may choose to use a wire fish to help with passing the blue bullet connector end of the power wire into the cab of the vehicle.
• Once the power wire is through the firewall, pull the slack into the driver floor board.
• Continue routing the power wire through the factory wiring channel along the drivers side towards the rear seat. 
• Secure any loose wire in the engine bay using the provided zip ties.

Step 4

Routing the main harness:

• Start with the connections for the amplifier and subwoofer near where you removed the rear storage cubby.
• Route the opposite end of the main harness with the T-harness end:
• Start along the bottom of the C-pillar and continue through the factory wiring channel near the rear door on the driver side. 

• Continue in the factory wiring channel under the B-pillar and through the wiring channel near the driver front door until you reach the front seat mount support
• Route the T-harness end of the main harness under the carpet towards the transmission tunnel.
• Continue along the floor towards front side of the center console (Towards the dash).
• Route the T-harness up into the lower dash cavity and towards the radio.
• At this point, you will want to remove the radio fully to gain access to the connections. 
• Continue running the T-Harness up the inside of the dash and towards the main radio connections. 

Step 5

Making connections to your 2016-2019 head unit:

• Factory Head Unit:
• Disconnect the 10 pin & 6 pin connector from the back of the head unit.
• Connect male end of the Alpine T-Harness to 10 pin & 6 pin locations in the back of head unit. 
• Connect 10 pin & 6 pin connectors from vehicle to female end of the Alpine T-Harness.
• Aftermarket Head Unit:
• Disconnect the 10 pin & 6 pin connector from the back of the head unit.
• Connect male end of the Alpine T-Harness to 10 pin & 6 pin locations in the back of head unit. 
• Connect 10 pin & 6 pin connectors from vehicle to female end of the Alpine T-Harness.
• Connect RCA's to RCA outputs from aftermarket radio:
• Front
• White to White
• Grey to Red
• Rear
• Green to White
• Purple to Red
• Sub
• White to White
• Red to Red

Making connections to your 2020-2023 head unit:

• Factory Head Unit:
• Disconnect the 10 pin connector from the back of the head unit.
• Connect male end of the Alpine T-Harness to 10 pin location in the back of head unit. 
• Connect 10 pin connector from vehicle to female end of the Alpine T-Harness.
• If needed: Connect the provided blue remote wire with male bullet connector end to blue remote wire from Alpine main harness. 
• Use the provided T-tap to connect to the Grey wire.

.     

• Aftermarket Head Unit:
  • Disconnect the 10 pin connector from the back of the head unit.
  • Connect male end of the Alpine T-Harness to 10 pin location in the back of head unit. 
  • Connect 10 pin connectors from vehicle to female end of the Alpine T-Harness.
  • Use provided bullet connectors to connect remote turn on wire (Blue with White Stripe) to your aftermarket head unit. 
  • Connect RCA's to RCA outputs from aftermarket radio:
  • Front
  • White to White
  • Grey to Red
  • Rear
  • Green to White
  • Purple to Red
  • Sub
  • White to White
  • Red to Red

Step 6

Installing the bass control knob:

• Use a 9/32 drill bit to create the subwoofer level knob opening. 
• A panel blank is highly recommended. 
• Use the provided nut to secure it and place the knob on the dial. 

Step 7

Replace your radio into the dash:

• Now that your main wiring harness is connected, make sure that any other connections that may have been removed are reconnected. 
• Place your head unit back into the dash and secure with the four factory 10 mm bolts. 
• Do not completely reassemble your dash at this time. We will want to test functionality before completely putting the truck back together. 

Step 8

Connecting the ground wire:

• Using the provided Alpine ground wire, attach the ring terminal to the factory rear seat bolt under the rear middle seat bracket.

Step 9

Modifying the rear storage compartment:

• Trim the left side (towards the center of the truck) of the rear plastic compartment. You may also use a 2.5 inch hole saw.

• Remove the trimmed piece of plastic.

Step 10

Installing the rear storage compartment:

• Replace the C-pillar trim and press into place. 
• Replace the rear storage compartment back into the truck.
• Insert the main harness through the opening in the plastic. 
• Make the two connections from the main Alpine harness to the amplifier.
• Secure the amplifier bracket to the plastic compartment using one of the provided bolts.
• Note: Some vehicles will not have the lower bolt position.

• Place the subwoofer near the storage cubby and make the connection to the subwoofer. 
• Connect the White 14 pin connector to subwoofer.
• Connect the RCA's from the main harness to subwoofer:
• Red to Red
• White to White

• Slide the subwoofer into the lower amplifier bracket.
• Secure the subwoofer bracket to the factory mounting locations using the provided bolts and standoff spacers. 

Step 11

Connect the power wire to the battery:

• Use a 10 mm or 12 mm wrench to remove the nut from the positive battery terminal. 
• Place the ring terminal from the Alpine power wire on the positive terminal and secure with factory nut. 
• It is completely normal to get a small spark when placing the ring terminal on the battery. 

Step 12

Test your system functionality:

• Power on your vehicle and test functionality. 
• Find a song that will play continuously for a few minutes:
• Check Balance/Fade setting to ensure all speakers are playing appropriately
• Below is the recommended amplifier setting for use with a Factory Head Unit:

• Below is the recommended amplifier setting for use with an Aftermarket Head Unit:

Once you have confirmed that your system is working and you have set the gains to your liking, reassemble your vehicle and enjoy your new amplified system!

Step 13

Reassembly of vehicle:

• Replace the weather seal around the rear door.
• Replace the seat bracket for the rear seat and secure using the factory 12 mm bolts.
• Replace the seat back and secure with the factory 14 mm bolts.
• Replace the bolt covers in the lower part of the back seat.
• Flip the seat up and replace the head rest.
• Replace the B-pillar trim by pressing into place. 
• Secure the weather seal around the B-pillar.
• Secure the 14 mm bolt that holds the bottom seat belt mount. 
• Replace the kick panel on the driver side and secure with button retainer. 
• Replace the driver door and driver rear door sills by pressing into place.
• Tighten the four 10mm bolts that secure the radio. 
• Replace the dash trim by pressing in. 

Troubleshooting:

Check the following items behind the head unit:

Factory head unit:

• Are the main vehicles connectors fully seated?
• Is the remote wire from the amplifier harness connected to the radio with a T-tap or T-Harness?
• If you're using a T-tap do you have a solid contact between the wires? You will know if you have a solid connection when the blue indicator light on the subwoofer is illuminated.

Aftermarket head unit:

• Are the main vehicles connectors fully seated?
• Are the RCA connections fully seated?
• Is the remote wire from the amplifier harness connected to the radio harness?
• Please ensure that the subwoofer output is turned on in the settings menu of the head unit.

Check the following items at the amplifier:

• Are the front and rear gains set to low/off?
• Double check the dip switches on the amplifier, the recommended settings can be found in the installation guide above.

Check the following items on the subwoofer:

• Is the input selector in the out position and set to "Remote"?
• Do you have a solid blue indicator light?
• Check the gain and crossovers dials, are the dials set to low/off?
• Do you have the RCA adapter connected from the amplifier harness to the RCA connections on the subwoofer?
• If not, please use the following instructions to add the subwoofer RCA to the main harness:

1. 1. Locate the red 4 pin connector on the main harness near the subwoofer.
   2. Disconnect the male and female ends of the red 4 pin connector.
   3. Connect the RCA adapter (located in the spare parts bag), attach the male 4 pin connector from the RCA's to the female red 4 pin connector.
   4. Connect the RCA's to the RCA inputs on the subwoofer.
   5. Adjust subwoofer gain on subwoofer with music playing to achieve preferred setting.

Once you have verified that the connections are correct and that the amplifier and subwoofer are working, here are a few more items to consider:

• If you are using this kit with a factory head unit, it is important to note that the factory unit output is voltage regulated. This means that the higher the volume number, the more power the head unit puts out. If you have the amplifier gains set to high with a low volume number on the head unit, when you increase the volume on the head unit the door speakers will peak out before enough signal has been sent to the subwoofer to produce an a desirable level of bass.
• Our recommendation is the tune the amplifier and subwoofer using the following steps after installation is complete:
  • Turn the gain adjustments on the amplifier and subwoofer all the way to the left or the lowest setting.
  • Find a song that will play for at least a few minutes.
  • Turn up the volume on your head unit to about 75% of the MAX volume.
  • Using a small flathead screwdriver adjust the Front gains setting on the amplifier until your desired sound level is reached.
  • Repeat the same for the Rear gains setting on the amplifier.
  • Repeat once more for the Sub gain setting on the subwoofer.
  • Adjust the crossover setting on the subwoofer to desired level.
• This will set the overall sound level for your vehicle. If you start to notice distortion or that the sound is clipping or stopping you have set your gains to high!
  • You can further adjust to your liking using the EQ settings within your head unit.
• If you have an aftermarket head unit, please ensure that the subwoofer output is turned on in the settings menu of the head unit.

Congratulations on installing your new
Alpine 4 Channel Amplifier and Powered Subwoofer Kit from Trail Grid Pro!