Subwoofer

Installation of an aftermarket subwoofer in a 2007 Ram 3500, including wiring, mounting, and integration with the factory audio system.

Warnings

Tools required

Parts

• Subwoofer speaker × 1 — Aftermarket, sized to preference
• Subwoofer enclosure × 1 — Aftermarket, crew cab or regular cab specific
• Amplifier × 1 — Aftermarket, match to subwoofer requirements
• Amplifier wiring kit × 1 — Minimum 8-gauge for typical installation
• RCA cables × 1 — Shielded, appropriate length
• Line output converter (LOC) × 1 — Only if factory system has no RCA outputs
• Inline fuse holder and fuse × 1 — Sized to amplifier requirements
• Butt connectors and ring terminals × 1 — Appropriate gauge for wiring kit
• Grommet for firewall pass-through × 1 — Rubber grommet for power wire

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery terminal and wait 2 minutes for airbag system to discharge
3. Determine subwoofer and amplifier mounting locations (behind rear seat is common for crew cab)
4. Plan wire routing from battery through firewall to amplifier location and from head unit to amplifier
5. Verify all components are compatible and gather necessary hardware

Procedure

1. 1

   Remove rear seat bottom cushion
   For crew cab models, lift front edge of rear seat bottom cushion firmly upward to release retaining clips. Pull cushion forward and out of vehicle. For regular cab, skip this step and plan alternative amplifier mounting location such as behind driver seat or in storage compartment.
2. 2

   Install amplifier mounting location
   Mount amplifier to rear wall or floor behind seat using self-tapping screws or bolts into solid metal. Ensure amplifier is level and has at least 2 inches clearance on all sides for ventilation. For carpet areas, cut carpet to access metal mounting surface. Verify no fuel tank, brake lines, or wiring behind mounting area before drilling.
3. 3

   Route power wire from battery
   Locate existing firewall grommet on driver side near battery (typically near brake booster or wiring harness pass-through). Create small slit in grommet and feed power wire from engine bay into cab using fish tape. Install rubber grommet around wire to protect from chafing. Route wire along driver side interior, under door sills and carpet to amplifier location. Secure with zip ties every 12 inches to prevent rattling.
   ⚠Keep power wire at least 12 inches away from factory ECM and PCM wiring to prevent electromagnetic interference.
4. 4

   Install inline fuse holder
   Install inline fuse holder on power wire within 18 inches of battery positive terminal. Do not install fuse yet. Use ring terminal to connect power wire to battery positive post, but do not tighten yet as battery is still disconnected.
5. 5

   Access radio and install signal wiring
   Remove center dash trim panel using panel removal tools to access factory radio. Remove radio mounting screws (Torx or hex head) and pull radio forward to access rear connectors. If factory radio has RCA outputs, connect RCA cables directly. If no RCA outputs, identify rear speaker output wires (consult factory wiring diagram) and connect line output converter to speaker wires using butt connectors. Route RCA cables along passenger side interior to amplifier location, keeping separate from power wire.
6. 6

   Establish ground connection
   Locate solid chassis ground point within 2 feet of amplifier (behind rear seat kick panel or floor bolt). Remove paint from metal surface using wire brush or sandpaper to expose bare metal. Connect ground wire from amplifier using ring terminal and secure with existing bolt or self-tapping screw. Verify ground continuity with multimeter between ground point and battery negative terminal (should read less than 0.5 ohms).
7. 7

   Connect amplifier wiring
   Connect power wire to amplifier positive terminal, ground wire to amplifier ground terminal, and RCA cables to amplifier input. Connect a remote turn-on source to the amplifier remote terminal — either the factory head unit's switched amp-turn-on/antenna lead (verify with a factory wiring diagram and confirm it is switched with ignition) or, if none is available, the signal-sensing remote output of the line output converter. If using line output converter, connect LOC remote output to amplifier remote input.
8. 8

   Install subwoofer enclosure
   Position subwoofer enclosure in desired location (typically behind rear seat for crew cab, behind front seats for regular cab). Secure enclosure using L-brackets or bungee cords to prevent movement during driving. Ensure enclosure does not interfere with seat operation or passenger safety.
9. 9

   Wire subwoofer to amplifier
   Run speaker wire from amplifier output terminals to subwoofer. Match polarity carefully (positive to positive, negative to negative). Secure wiring to prevent chafing or interference with seat mechanisms. For dual voice coil subwoofers, wire according to manufacturer specifications to achieve desired impedance.
10. 10

    Reconnect battery and initial test
    Reconnect negative battery terminal. Insert fuse into inline fuse holder on power wire. Turn ignition to accessory position and verify amplifier power light illuminates. Turn on radio and verify amplifier turns on with its power/status LED (color varies by manufacturer). If amplifier does not power on, verify all connections and fuse continuity.
11. 11

    Configure amplifier settings
    Set amplifier gain to minimum position. Set low-pass crossover to 80-100 Hz for typical subwoofer application. If amplifier has bass boost, leave at 0 dB initially. Play test track with consistent bass content and slowly increase gain until distortion is heard, then reduce gain slightly. Adjust crossover frequency to blend with main speakers.
12. 12

    Secure all wiring and reinstall panels
    Secure all wiring with zip ties to prevent rattling. Ensure no wires are pinched by seat mechanisms or trim panels. Reinstall rear seat bottom cushion by inserting rear hooks first, then pressing down firmly on front edge until clips engage. Reinstall center dash trim and radio trim panels. Verify all panels are secure and gaps are even.

Reassembly

1. Verify all interior trim panels are properly seated and clips engaged
2. Ensure rear seat cushion is securely locked in place and operates normally
3. Confirm no wiring is visible or pinched by moving components
4. Route and secure any excess wiring to prevent rattles

Verification

• Turn ignition to accessory and verify amplifier powers on when radio is activated
• Play music with bass content at various volume levels and verify no distortion or rattling
• Test subwoofer at low, medium, and high volume levels for proper output
• Verify all vehicle functions remain operational including seats, radio, and other accessories
• Check that no warning lights are illuminated on dash
• Operate rear seat through full range of motion to ensure no interference with wiring or enclosure

More procedures for this vehicle