Scosche S3TA03 S3-1 Interface Harness
For 2003-11 Toyota JBL / Lexus Premium Audio Systems
Applications
LEXUS Premium Sound
(Not compatible with Mark Levinson)
- 2008-10 ES330/350
- 2007-08 GS350
- 2008 GX470
- 2007-10 RX350
TOYOTA JBL & JBL Synthesis
- 2003-10 4Runner
- 2007-09 Avalon
- 2007-11 Camry
- 2008-11 Highlander
- 2004-11 Prius
- 2004-11 RAV4
- 2005-11 Sequoia
- 2004-11 Sienna
- 2006-08 Solara
- 2005-11 Tacoma
- 2004 Tundra W/RSE 8-speaker JBL system only
- 2005-06 Tundra W/JBL Except 6 Speaker system
- 2007-11 Tundra
Installation Notes
The S3TA03 harness is designed for use with the Scosche S3-1 interface. It allows you to replace your Factory OEM stereo while retaining the Factory Digital JBL/Premium audio system and Steering wheel controls when the vehicle is so equipped. Please review this information for specific installation in selected Toyota and Lexus vehicles. For steering wheel control information, consult the S3-1 interface instructions.
JBL / JBL SYNTHESIS and LEXUS AMPLIFIED AUDIO SYSTEMS
These Factory-amplified sound systems are driven and digitally controlled by a single set of Left/Right input channels only. The Aftermarket radio does not have the ability to control Front to Rear fade adjustment. The fader will be set to center by the interface software.
FACTORY AUX-INPUT RETENTION
The S3TA03 harness includes a set of Left/Right (White/Red) input connections for retaining the Factory Auxiliary input location on some 2005-UP vehicles. If your Aftermarket stereo has a set of rear Auxiliary input connection, then use these plugs to retain the use of the original Factory Aux-in location.
Wiring Instructions
ATTENTION! INSTALLER NOTE: Before removing FACTORY Toyota stereo, turn ON and adjust to 1/2 VOLUME level to prevent low volume output AFTER installation.
- Disconnect the Negative battery cable from the battery to avoid short circuits.
- Remove and unplug Factory stereo.
- Match and connect the Power/ground wires from the S3-1 Vehicle specific harness to the wires from your stereo. The color codes on the Scosche harness are designed to match most Aftermarket stereos.
- Wire the Front RCA leads from the RCA audio input connections on the harness. Gray RCA is Right input and White RCA is Left input.
- Optional: If you are using the Aux input RCA leads to retain the Factory Aux input location, connect the Red/White audio cables from the S3-1 harness to the Auxiliary input at the back of the Radio.
- Tape any unused wiring to prevent short circuits.
- Connect all harnesses between S3-1, Vehicle and Aftermarket stereo.
Wire Color Codes
| Wire | Function |
|---|---|
| White RCA | Left Channel Audio input |
| Gray RCA | Right Channel Audio input |
| Black | Chassis Ground |
| Yellow | +12V Constant Power |
| Red | +12V Accessory / R.A.P output |
| Orange | Illumination |
| Orange/White | Dimmer |
| Blue | +12V Power Antenna/ (Amplified antenna) |
| Blue/White | +12 Remote Output |
| White RCA | Left Aux input (from Factory Auxiliary connection) |
| Red RCA | Left Aux input (from Factory Auxiliary connection) |
Troubleshooting
PROBLEM
TIP/SOLUTION
- Vehicle does not recognize the interface
It is recommended to turn "ON" the ignition key to the "RUN" position for approximately 2 seconds and "OFF" twice before beginning the first test of the newly installed interface. - LED does not turn on
It is recommended to check "ALL" wiring connections and also ensure that the power wires are getting their proper +12 volts. - Low volume with aftermarket radio
Re-install factory radio, turn on and adjust to 1/2 volume. - No audio
Possible non-digital JBL system. See Figure 2.
Wiring Diagram Description
The wiring diagram illustrates the connection between an aftermarket stereo, the Scosche S3TA03 harness, and the S3-1 interface module for integration into Toyota and Lexus vehicles with JBL or Premium audio systems. The aftermarket stereo connects to the S3TA03 harness via its RCA audio outputs (typically Gray for Right, White for Left) and steering wheel control inputs (3.5mm or blue connector). The S3TA03 harness then connects to the S3-1 interface module, which in turn connects to the vehicle's factory wiring. An optional AUX input retention feature is also shown, where the S3TA03 harness's Red/White RCA cables connect to the aftermarket stereo's rear AUX input if available, preserving the factory auxiliary port functionality. The diagram also shows steering wheel control outputs from the aftermarket stereo connecting to the S3-1 interface module, which then interfaces with the vehicle's steering wheel controls.
Key Connections Shown:
- Aftermarket stereo 2-Channel RCA inputs (Gray: Right, White: Left) connect to the S3TA03 harness.
- Optional AUX input retention uses Red/White RCA cables from the S3TA03 harness to connect to the aftermarket stereo's rear AUX input.
- Steering wheel control outputs from the aftermarket stereo (e.g., 3.5mm for Alpine, Clarion, JVC, Pioneer, Sony; or a blue connector for Kenwood) connect to the S3-1 interface module.
- The S3-1 interface module connects to the vehicle's main harness and steering wheel control module.
Figure 3: 20-pin Toyota JBL Radio Connector (Power/Audio Plug)
Figure 3 details the pinout for the 20-pin connector used for power and audio in Toyota JBL radios. The pins are numbered 1 through 20. A critical note specifies that Pin 6 is used to differentiate between system types: if Pin 6 is vacant, it indicates a Non-digital JBL system requiring a TA03B adapter; if Pin 6 has a wire present, it signifies a Digital JBL system requiring the S3-1/S3TA03B. The diagram shows the plug with wires exiting towards the viewer.
Scosche Stereo Installation Components
The S3TA03 harness and S3-1 Steering Wheel module are key components for integrating an aftermarket stereo into compatible Toyota and Lexus vehicles. These are part of Scosche's range of stereo installation components and stereo dash kits.
