Upgrading your Jeep Wrangler 1999 with a subwoofer can make a huge difference in your driving experience. The factory sound system often lacks deep bass, making music sound flat. Installing a subwoofer brings your favorite tracks to life and adds excitement to every drive. Many Jeep owners worry this upgrade is difficult, but with the right tools and clear steps, you can complete the installation yourself. This guide explains everything you need to know, from choosing the right subwoofer to wiring it safely.
Choosing The Right Subwoofer For Your Jeep Wrangler 1999
Before you start, you need the right subwoofer and accessories. The Jeep Wrangler has a compact interior, so space matters. Most owners choose between an under-seat subwoofer or a cargo-area box. Here’s a quick comparison:
| Subwoofer Type | Pros | Cons |
|---|---|---|
| Under-Seat Subwoofer | Saves space, hidden from view | Limited bass output, smaller size |
| Cargo-Area Box | Powerful bass, easy to upgrade | Takes up cargo space, visible |
The most popular sizes are 8-inch or 10-inch subwoofers, as they fit well in the Wrangler. Make sure your subwoofer matches your amplifier’s power and your music preferences. For most drivers, a powered (all-in-one) subwoofer is the easiest to install.
Tools And Materials Needed
Gather these items before you begin:
- Subwoofer (powered or passive)
- Amplifier (if using a passive subwoofer)
- Amplifier wiring kit (power wire, ground wire, RCA cables, fuse)
- Speaker wire
- Wire crimper/stripper
- Socket and screwdriver set
- Zip ties
- Electrical tape
- Panel removal tool
If you’re missing any tools, you can rent them at auto parts stores.
Preparing Your Jeep Wrangler
Turn off your Jeep and disconnect the negative battery terminal before starting. This prevents any electrical shorts or shocks.
Remove the rear seats if you need extra room, especially for cargo-area boxes. Take out floor mats and clear the installation area. Check for existing wiring or obstacles under the carpets.
Inspect the path from the battery to the cargo area. Most Jeep Wranglers have rubber grommets in the firewall for routing wires. Plan your wiring route to avoid pinching or heat sources.
Installing The Subwoofer And Amplifier
Step 1: Mounting The Subwoofer
Place the subwoofer in your chosen location under a seat or in the cargo area. Mark and drill mounting holes if needed.
Secure the subwoofer firmly so it doesn’t move during off-road driving.
If you use a passive subwoofer, mount the amplifier nearby. Many powered subwoofers include mounting hardware.
Step 2: Running Power And Ground Wires
Route the power wire from the battery through the firewall. Always add an inline fuse within 18 inches of the battery to protect your Jeep.
Run the wire along the door sills or under the carpet, securing it with zip ties. Avoid routing near airbag wiring (often marked in yellow).
Connect the power wire to the amplifier or powered subwoofer.
For the ground wire, find a clean, unpainted metal surface close to the subwoofer. Sand the metal, attach the ground terminal, and bolt it down tightly.
A poor ground can cause noise or weak bass.
Step 3: Connecting The Audio Signal
You have two main options for getting sound to your subwoofer:
- RCA cables from an aftermarket head unit (best quality)
- Speaker-level inputs from factory speaker wires (if you have the stock radio)
If using RCA cables, run them down the opposite side of the vehicle from the power wire to reduce noise. For speaker-level inputs, use wire taps to connect to the rear speaker wires.
Connect the remote turn-on wire (often blue) to your head unit’s remote output. This wire tells the amplifier or subwoofer to turn on with your radio.
Step 4: Final Wiring And Testing
Double-check all connections. Secure loose wires with zip ties. Reconnect the negative battery terminal.
Test the system by turning on your Jeep and playing music. Adjust the gain and bass settings on the amplifier or subwoofer.
Start at low volume to avoid damaging the speakers.
Here’s a summary of the most important wiring tasks:
| Wire | Connects To | Important Tip |
|---|---|---|
| Power Wire | Battery (+) | Use inline fuse |
| Ground Wire | Chassis | Clean metal surface |
| RCA/Signal | Head Unit or Speakers | Run away from power wire |
| Remote Turn-On | Head Unit | Enables amp/subwoofer |
Tuning And Finishing Touches
Once everything works, spend time tuning your subwoofer. Every Jeep interior is different, so use these tips:
- Start with the gain at minimum and increase slowly.
- Adjust the low-pass filter to cut frequencies above 80 Hz.
- Use bass boost sparingly—too much can damage the subwoofer.
- Listen for rattles or vibrations. Add foam or insulation if needed.
A common mistake is setting the gain too high, which causes distortion. Small adjustments make a big difference.
For extra security, bolt the subwoofer box down or use locking straps if you drive with the top down.
Safety And Legal Tips
Installing a subwoofer changes how your Jeep sounds inside and outside. Be careful with volume levels loud bass can attract attention or annoy neighbors.
In some states, high sound levels are illegal on public roads.
If you’re unsure about any wiring, ask a professional installer for advice. Incorrect wiring can damage your Jeep’s electrical system or even cause a fire.
For more technical details on car audio installation, visit the official Crutchfield guide.
Frequently Asked Questions
How Much Does It Cost To Install A Subwoofer In A Jeep Wrangler 1999?
Most DIY installs cost between $150 and $400 for a powered subwoofer and wiring kit. Professional installation adds $100–$200 in labor. Costs increase with high-end equipment.
Can I Keep My Factory Radio With A New Subwoofer?
Yes, you can use speaker-level inputs to connect a subwoofer to the factory radio. Powered subwoofers often include these connections.
Do I Need A Separate Amplifier For My Subwoofer?
If you use a powered subwoofer, the amplifier is built-in. For passive subwoofers, you need a separate amp matched to the sub’s power rating.
Will Adding A Subwoofer Drain My Jeep’s Battery?
A properly installed subwoofer should not drain your battery. Make sure to use an inline fuse and connect the remote turn-on wire to avoid power draw when the Jeep is off.
Is It Safe To Install A Subwoofer Myself?
Yes, if you follow safety steps like disconnecting the battery and using the correct wiring. If you’re unsure, consult a professional installer.
Upgrading your Jeep Wrangler 1999 with a subwoofer is one of the most rewarding audio improvements you can make. With careful planning and the right tools, you’ll enjoy rich, powerful bass on every trip—making your Jeep as fun on the inside as it is on the outside.
