Dual Amplifier Installation Guide '18- '23 JL Wrangler/ '20-'23 JT Gladiator

This guide will walk you through installing a dual-amplifier setup in your Jeep Wrangler JL or Gladiator JT, including a 4-channel amplifier under the driver seat and a mono amplifier under the passenger seat. This installation uses a 4-gauge dual amp power kit, with both amps grounded to the factory grounding locations under each seat (near the transmission tunnel and center console).

A detailed installation video is provided at the bottom of this guide to assist with the process. If you have any questions or need support during installation, we’re just a call away Monday–Friday, 9 AM–5 PM EST.

Before beginning, we suggest checking all parts and calling in or emailing if you are missing any parts for your system! We want to make sure you have everything to make the system work, below is a " What's In The Box" diagram pointing out all parts you will need for the install to work smoothly! "

Step 1: Remove Driver and Passenger Seats

• Use an 18mm socket to remove the four seat bolts.

• Use a T45 Torx to remove the seatbelt bolt (if needed).

• Tilt or fully remove both seats for easier access.

Step 2: Route Power and Ground Wires

Power Wire: Route the 4-gauge power wire from the battery through the firewall (driver-side footwell).

Distribution Block: Mount the block near the center console beneath the carpet, splitting power to both amplifiers.

Ground Wires:

• 4-Channel Amp Ground: Use the factory ground point under the driver seat (near the transmission tunnel).
• Mono Amp Ground: Use the factory ground point under the passenger seat (same location on the opposite side).

• Secure all ground connections tightly to avoid noise issues.

Step 3: Remove Radio & Access Signal Wiring

Factory Radio Installation (Using PAC Module)

If connecting to the factory radio, install the PAC AP4-CH41 module behind the glove box. Use the provided T-harness to connect the PAC module to the radio harness. If your Jeep isn’t factory amplified, make sure DIP switch #4 is DOWN on the PAC module.

Connect the 9-wire harness from the PAC module:

• Match speaker wires color to color.
• Connect the blue remote turn-on wire from the PAC module to the blue amp remote wire (pre-terminated with a bullet connector).

• Run RCA cables from the PAC module to both amplifiers:

• Front & Rear RCA → to the 4-channel amp under the driver seat.

• Subwoofer RCA → to the mono amp under the passenger seat.

Aftermarket Radio Installation

If using an aftermarket radio, connect the RCA cables from the radio’s front, rear, and subwoofer pre-outs to the amplifiers. Connect the blue remote turn-on wire from the radio harness to both amplifiers using a Y-splitter or distribution block.

Non OEM Amplified Bundle

Step 6: Adjust Amplifier Settings

4-Channel Amp Settings:

• Gain: Start at 0, then increase gradually until you hear distortion, then back down slightly.
• Crossover: High-pass filter (HPF) ON for front and rear speakers, set around 3 o’clock (80–100Hz).
• Bass Boost: OFF (use radio EQ instead).
• Fader/Input Level: Set to Low (pushed out).

Mono Amp Settings:

• Gain: Start at 0, increase until the subwoofer reaches desired level without distortion.
• Low-Pass Filter (LPF): Set between 80–100Hz (around 9 o’clock).
• Bass Boost: Minimal (9–12 o’clock max).
• Subsonic Filter (if available): Set at 25–30Hz to protect the sub.

6) Test the system-

• Prior to installing all the trim pieces and the seat, you will want to test the system. You will need to set the radio into the place and install the connections at the bottom trim piece to power on the Jeep. 
• A good measure is to start with the amplifier adjustments as recommended above.
• Power on the Jeep and ensure that all speakers and the subwoofer (if installed), are reacting. Now is a good time to adjust the gain further if needed. 
  • Adjust all of the radio EQ settings to "0
  • Lower the radio volume to "0"
  • Lower all of the gains on the amp to "0"
  • Crossover adjustments can be set to just below half
  • Increase the volume on the radio to 75%
  • Increase the gain knob slowly until you hear a distortion from the speakers.
  • Slightly lower the gain knob and move on the next gain knob (if applicable)
  • You can now use the radio's EQ settings to add a little bit adjustments based on sound preference.
• Adjusting gain-
• Bolt seat down, secure radio, replace trim pieces, etc.

7) ENJOY YOUR NEW SYSTEM!!

Installation video by Trail Seven, to be used with the written instructions below: