The third-generation Lexus GS300 (S190) marked a major leap forward for the GS lineup. Gone was the legendary 2JZ inline-six, replaced by a more modern 3.0L 3GR-FSE V6, while the interior received a complete technological makeover.
This generation introduced features that were cutting-edge in 2006:
- Push-button start
- SmartAccess keyless entry
- Large touchscreen display
- Bluetooth connectivity
- Factory navigation
- Backup camera
- Mark Levinson premium audio
- Steering wheel audio controls
- Voice commands
Unfortunately…
It also became significantly more complicated to install an aftermarket stereo.
Toyota engineers apparently decided, “What if we connected literally everything to the radio?”
Mission accomplished.
2006–2007 Lexus GS300 Stereo Wiring Diagram
Unlike previous generations, the S190 uses additional wiring for illumination, amplifier activation, and the power antenna.
Radio Power Wiring
| Wire Function | Factory Wire Color |
|---|---|
| Constant 12V Battery | Blue/Yellow |
| Switched Accessory | Brown |
| Ground | Gray |
| Illumination | Green |
| Power Antenna | Black/Red |
| Amplifier Turn-On | White/Blue |
| Dimmer | N/A |
Front Speaker Wiring
| Speaker | Positive | Negative |
|---|---|---|
| Left Front | Pink | Purple |
| Right Front | Light Green | Blue |
Rear Speaker Wiring
| Speaker | Positive | Negative |
|---|---|---|
| Left Rear | Black | Yellow |
| Right Rear | Red | White |
2008–2011 Lexus GS300 Wiring
Toyota made very few changes to the stereo wiring during the later years of the S190 platform.
Whether you’re working on a:
- 2008 GS300
- 2009 GS300
- 2010 GS300
- 2011 GS300
…the factory radio wiring generally follows the same layout as the earlier S190 models.
Always verify wire colors with a multimeter before making permanent connections, especially if your vehicle includes factory navigation or the Mark Levinson audio package.
Does My GS300 Have Mark Levinson Audio?
Many third-generation GS300 models were equipped with one of the best factory audio systems Lexus ever offered.
The optional Mark Levinson Premium Surround Sound System includes:
- External digital amplifier
- Premium speakers throughout the cabin
- Center channel speaker
- Factory subwoofer
- Digital signal processing
- Navigation integration (on equipped models)
If your door speaker grilles say Mark Levinson, congratulations.
You also just made your stereo installation more expensive.
Replacing the Factory Navigation Radio
One of the biggest questions we receive is:
“Can I replace the factory navigation screen?”
The answer is:
Yes… but it’s not always simple.
Depending on the year and equipment, the factory touchscreen may control:
- Climate controls
- Vehicle settings
- Audio system
- Backup camera
- Navigation
- Clock functions
- Bluetooth
Replacing the radio often requires:
- CAN Bus integration module
- Steering wheel control interface
- Climate retention module
- Factory amplifier integration harness
Skipping these components may leave you with a beautiful new touchscreen…
…that can’t adjust your air conditioning.
Not ideal in August.
Factory Speaker Locations
Most S190 GS300 models include:
Front
- Door-mounted woofer
- Dash tweeter
Rear
- Rear door speaker
- Rear deck speaker (premium audio)
Premium Mark Levinson systems may include:
- Center channel speaker
- Additional subwoofer
- More amplifier channels
Speaker sizes vary depending on trim level, so verify before ordering replacements.
Steering Wheel Audio Controls
The S190 uses steering wheel-mounted controls that communicate electronically with the factory radio.
To retain these buttons after installing an aftermarket stereo, you’ll typically need a steering wheel control interface compatible with your new head unit.
Popular aftermarket radios from:
- Kenwood
- Pioneer
- Sony
- Alpine
- JVC
…all support steering wheel control retention with the proper adapter.
Because reaching three inches farther to adjust the volume is apparently too much cardio.
Backup Camera Integration
Many late-model GS300s include a factory backup camera.
Fortunately, most aftermarket integration modules allow you to retain the OEM camera while upgrading to a modern multimedia receiver.
This lets you enjoy:
- Apple CarPlay
- Android Auto
- Bluetooth streaming
- Factory backup camera
- Factory steering wheel controls
It’s one of the best upgrades you can make without sacrificing factory functionality.
Factory Amplifier Notes
Before connecting your new stereo, determine whether your vehicle uses:
- Factory amplifier
- Mark Levinson amplifier
- Standard audio package
The amplifier turn-on wire for the S190 is:
White/Blue
Without activating the amplifier, your new stereo may appear to function normally…
…while producing approximately the same amount of sound as two people whispering in another room.
Best Stereo Upgrades for the Third-Generation GS300
The S190 benefits tremendously from a modern multimedia receiver.
Recommended features include:
- Wireless Apple CarPlay
- Wireless Android Auto
- HD touchscreen
- Wireless Bluetooth
- Dual USB ports
- High-voltage preamp outputs
- Time alignment
- Built-in DSP
- Backup camera support
Combined with upgraded speakers and a quality amplifier, the GS300 can deliver sound quality that rivals many new luxury sedans.
Installation Tips
Before beginning your installation:
✔ Disconnect the negative battery cable.
✔ Save your radio presets.
✔ Label every connector.
✔ Photograph the factory wiring.
✔ Test the new radio before reinstalling trim panels.
✔ Verify amplifier operation before closing the dashboard.
Trust me.
Nothing is more frustrating than discovering one loose connector…
…after you’ve already snapped 47 pieces of Lexus interior trim back together.
Frequently Asked Questions
Can I replace the factory navigation system?
Yes, but vehicles equipped with factory navigation often require additional integration modules to retain climate controls, factory amplifiers, and steering wheel controls.
Does every 2006 GS300 have Mark Levinson audio?
No.
Mark Levinson was optional on many trim levels.
The easiest way to identify it is by looking for the Mark Levinson logo on the speaker grilles.
Can I keep my factory backup camera?
In most cases, yes.
Several aftermarket interfaces allow the OEM camera to function with a modern multimedia receiver.
Is installing an aftermarket stereo difficult?
Compared to earlier GS300 generations, yes.
The S190 is significantly more integrated electronically, making proper wiring adapters and interface modules highly recommended.
Final Thoughts
The third-generation GS300 represents the point where Lexus transformed the GS into a technology-focused luxury sedan. While the increased integration makes stereo upgrades more involved than the earlier S140 and S160 models, the rewards are worth it. With the correct wiring harnesses, amplifier interfaces, and steering wheel control adapters, you can enjoy modern features like wireless Apple CarPlay and Android Auto without sacrificing the premium feel that made the GS300 one of Lexus’s standout sedans.
After all, if you’re driving a luxury sedan known for comfort and refinement, your playlist deserves an upgrade too.
