The second-generation Lexus GS300 (chassis code S160) is where the GS really hit its stride. Built from 1998 through 2005, this generation paired the bulletproof 2JZ-GE inline-six with updated styling, improved handling, and one of the nicest luxury interiors of its era.
If you’ve ever wondered why these cars have become favorites among drifters, VIP builders, and 2JZ enthusiasts, it’s because they offer Supra reliability wrapped in a comfortable luxury sedan.
Motor Trend even named the GS Import Car of the Year shortly after its debut, while Car and Driver placed it on its Ten Best list for three consecutive years.
For stereo enthusiasts, however, the S160 introduced a few new wrinkles. Depending on the year and trim level, your GS300 may include:
- Factory amplifier
- Premium audio system
- Navigation package
- Steering wheel audio controls
- SportDesign package
- Optional Mark Levinson audio (late production)
Knowing which system your car has before purchasing a head unit can save you from spending Saturday afternoon asking why nothing makes sound.
1998–2000 Lexus GS300 Stereo Wiring Diagram
The early S160 models retained wiring colors similar to the first generation, making aftermarket stereo installation relatively straightforward.
Radio Power Wiring
| Wire Function | Factory Wire Color |
|---|---|
| Constant 12V Battery | Blue/Yellow |
| Switched Accessory | Gray |
| Ground | Brown |
| Illumination | N/A |
| Dimmer | N/A |
| Power Antenna | N/A |
| Amplifier Turn-On | N/A |
Front Speaker Wiring
| Speaker | Positive | Negative |
|---|---|---|
| Left Front | Pink | Purple |
| Right Front | Light Green | Blue |
Factory speaker size:
5¼-inch
Location:
Front doors
Rear Speaker Wiring
| Speaker | Positive | Negative |
|---|---|---|
| Left Rear | Black | Yellow |
| Right Rear | Red | White |
Factory speaker size:
5¼-inch
Location:
Rear doors
2001–2005 Lexus GS300 Stereo Wiring
Good news.
Toyota didn’t reinvent the wheel.
The 2001 facelift brought revised headlights, taillights, grille, and interior upgrades, but the basic radio wiring remained largely unchanged. The facelift also introduced features like optional Xenon headlights and updated interior trim while keeping the familiar 2JZ-GE engine under the hood.
If you’re installing an aftermarket stereo in a 2001–2005 GS300, the wiring colors generally remain:
Radio Wiring
| Wire Function | Factory Wire Color |
|---|---|
| Constant 12V Battery | Blue/Yellow |
| Switched Accessory | Gray |
| Ground | Brown |
Speaker wiring remains:
Front Speakers
- Left (+): Pink
- Left (-): Purple
- Right (+): Light Green
- Right (-): Blue
Rear Speakers
- Left (+): Black
- Left (-): Yellow
- Right (+): Red
- Right (-): White
Always verify with a multimeter before making permanent connections, especially on late-production vehicles or those equipped with factory premium audio.
What About the SportDesign Package?
Beginning with the 2002 model year, Lexus introduced the SportDesign package for North America.
The package added:
- Sport-tuned suspension
- Rear lip spoiler
- Polished alloy wheels
- Titanium-look HID headlights
- Brushed aluminum interior trim
- Optional navigation
- Optional Mark Levinson premium sound system
While the suspension and styling upgrades are easy to spot, the audio system is where installers need to pay attention.
If your SportDesign model includes the Mark Levinson premium audio system, you’ll likely need:
- A premium amplifier integration harness
- A compatible steering wheel control interface
- A data retention module (depending on the aftermarket head unit)
Simply plugging a new radio into the factory connectors may result in…
Absolutely nothing.
Well, technically you’ll get dashboard lights.
Just not music.
Factory Speaker Locations
For most second-generation GS300 models:
Front
- 5¼-inch speakers
- Mounted in the front doors
Rear
- 5¼-inch speakers
- Mounted in the rear doors
Premium audio systems may also include:
- Dash-mounted tweeters
- Factory amplifier
- Additional center-channel speaker (navigation-equipped models)
Speaker sizes can vary slightly depending on trim level and factory audio package, so it’s always wise to remove a panel and verify dimensions before ordering replacements.
Factory Amplifier Information
Not every GS300 came with a standalone amplifier.
However, vehicles equipped with premium audio packages often include an external amp mounted behind interior trim panels.
Before purchasing an aftermarket stereo, verify:
- Whether the factory amplifier is present
- If the amplifier will be retained or bypassed
- Whether your installation harness supports amplified systems
Many “my new radio powers on but there’s no sound” complaints can be traced back to one overlooked amplifier connection.
Best Stereo Upgrades for the S160
The S160 dashboard accepts several popular double-DIN multimedia receivers with the proper dash kit.
Popular upgrades include:
- Wireless Apple CarPlay
- Android Auto
- Bluetooth hands-free calling
- HD Radio
- Backup camera support
- USB-C fast charging
- High-voltage RCA outputs for external amplifiers
- DSP tuning capabilities
Pairing a modern touchscreen with the GS300’s quiet cabin transforms the driving experience without sacrificing the car’s refined character.
Installation Tips
Before removing the factory radio:
✔ Disconnect the negative battery terminal.
✔ Label every connector.
✔ Photograph the factory wiring.
✔ Test the new stereo before reinstalling the dash.
✔ Verify speaker polarity.
✔ Don’t twist wires together and hope for the best.
Toyota engineers spent years designing this car.
Let’s not let a $4 crimp connector become the weakest link.
Frequently Asked Questions
Will a 1998 radio fit a 2005 GS300?
Generally yes, but trim pieces, factory options, and wiring harnesses may differ depending on model year and equipment level.
Does the SportDesign package change the wiring?
The basic radio wiring is similar, but vehicles equipped with the optional Mark Levinson audio system require additional integration hardware.
Can I install Apple CarPlay in my GS300?
Absolutely. With the proper dash kit and wiring harness, the S160 GS300 is an excellent candidate for a modern double-DIN multimedia receiver.
We’ll cover the 2006–2011 Lexus GS300 (S190), including:
- Complete radio wiring colors
- Power antenna and amplifier trigger wires
- Factory navigation integration
- Mark Levinson audio considerations
- Steering wheel control compatibility
- Premium amplifier wiring
- OEM speaker locations and installation tips
