Scosche S3GMLAN S3-1 Interface Harness
Installation Guide for GM LAN 29 Bit Data Systems (2006-Up)
Product Overview
The Scosche S3GMLAN S3-1 Interface Harness is designed for use with the Scosche S3-1 interface. It allows for the replacement of a factory OEM stereo while retaining essential factory warning chime and safety systems. This harness also enables the retention of factory steering wheel controls if the vehicle is equipped.
Applications
This harness is compatible with the following GM vehicles equipped with the LAN 29 Bit Data System (2006-Up):
Buick
- 2008-11 Enclave
- 2006-09 Lucerne
Cadillac
- 2007-11 Escalade/ESV/EXT
Chevrolet
- 2007-11 Avalanche
- 2008-11 Express Van
- 2006-11 Impala / SS
- 2006-07 Monte Carlo / SS
- 2007-11 Silverado
- 2007-11 Suburban
- 2007-11 Tahoe
- 2009-11 Traverse
GMC
- 2007-11 Acadia
- 2008-11 Savana Van
- 2007-11 Sierra
- 2007-11 Yukon/XL
Hummer
- 2008-09 H2
Saturn
- 2007-09 Outlook
Application Notes: Not compatible with OnStar or "Premium" Bose (y91/y92/z75) audio systems. Verify equipment codes by checking the service parts code sticker, usually located in the glove box, for "y91", "y92", or "z75".
Installation Notes
This document provides information for specific installation in GM LAN 29 Bit vehicles. For detailed steering wheel control information, consult the S3-1 interface installation instructions.
Testing for "Premium Bose" Systems
GM vehicles may have two types of Bose systems. The S3-1 interface is not compatible with Digital Premium Bose (y91/y92/z75) systems. To test:
- Rapidly turn the factory radio volume up and down.
- If the sound system reacts immediately, it is a Standard Bose system.
- If there is a slight delay in the system's reaction, the vehicle may have Premium Bose.
Alternatively, check the service parts code sticker in the glove box for "y91" or "z75" equipment codes.
Integrated Safety & Warning Chimes
Replacing the factory stereo without the S3-1 interface can result in the loss of audible safety and warning chimes. The vehicle's ECM (Electronics Control Module) may also store an error code, potentially causing service difficulties. The Scosche S3-1 sends proper data commands to the ECM to indicate a "healthy" status for diagnostic purposes.
Retained Warning & Safety Chimes:
- Parking assist
- Lights left on reminder
- Turn signal click
- Low fuel
- Folding mirrors (if equipped)
- Seatbelt warning chime
- Check Engine/Service indicator
- Key left in ignition reminder
- Low oil level
Wiring Instructions
- Disconnect the negative battery cable to prevent short circuits.
- Remove and unplug the factory stereo.
- Match and connect the Power/ground wires from the S3-1 Vehicle specific harness to the wires from your aftermarket stereo. Scosche harness color codes are designed to match most aftermarket stereos. Note that some wires for your new stereo may originate from the S3-1 interface box itself, not the vehicle connectors.
- Speaker Connections:
- For GM Standard Bose systems, the S3-1 speaker connections are pre-terminated with RCA jacks.
- For vehicles without a Bose system, cut off the RCA connectors and wire the speaker leads directly to the speaker wires from the new stereo. (Refer to diagrams for details).
- Tape any unused wiring securely to prevent short circuits.
- Proceed to the "Power Up (Initialization)" procedure.
Power Up (Initialization Procedure)
To ensure proper functionality of the S3-1's +12V RED Accessory wire, follow this procedure:
- With all doors and the hood closed, turn off all lights, and remove the keys from the ignition.
- Wait for 3 to 4 minutes without opening any doors, turning on lights, or inserting keys.
- Connect the Scosche Interface to the vehicle's radio harness and start the vehicle.
- Test the interface for functionality.
Wire Color Codes
General Wiring:
- White: Left Front Positive (LF+)
- White/Black: Left Front Negative (LF-)
- Green: Left Rear Positive (LR+)
- Green/Black: Left Rear Negative (LR-)
- Black: Chassis Ground
- Yellow: +12V Constant Power
- Red: +12V Accessory / R.A.P output
- Blue: +12V Power Antenna
- Gray: Right Front Positive (RF+)
- Gray/Black: Right Front Negative (RF-)
- Violet: Right Rear Positive (RR+)
- Violet/Black: Right Rear Negative (RR-)
- Orange: Illumination
- Blue/White: +12 Remote Output (Amp, radio on signal)
Navigation Connections:
- Violet/White: VSS Vehicle speed pulse signal
- Red/White: Reverse light trigger (+12V when in reverse gear)
- Yellow/Black: Parking Brake trigger (-12V when park brake ON)
- Orange/White: Auto illumination (Data controlled lighting output on some GM LAN applications with AUTO headlights enabled)
Note: The RED Accessory output wire is rated at 10A Max for most aftermarket headunit demands. Connecting additional +12V switched accessories to this output is not recommended and may damage the S3-1 module. A relay is needed if 10A output is insufficient (relay not included).
Note: Illumination & Auto illumination outputs are designed for headunit connections only.
Speaker / Audio Connections
- GM Bose (Excludes Premium Bose): Use RCA Low Level connections.
- Non-Bose: Use Speaker Wire, cut-off RCA's.
Wiring Diagrams
S3GMLAN Non-Bose Wiring Diagram
This diagram illustrates the connections for a non-Bose system. It shows the steering wheel output (e.g., Kenwood, Alpine, Clarion, JVC, Sony) connecting to the S3-1 Interface Module and the S3-1 Steering Wheel Module. The diagram indicates that RCA connections should be cut for non-Bose installation.
S3GMLAN Standard Bose Wiring Diagram
This diagram illustrates the connections for a standard Bose system. It shows the steering wheel output (e.g., Kenwood, Alpine, Clarion, JVC, Sony) connecting to the S3-1 Interface Module and the S3-1 Steering Wheel Module. The diagram specifies using 4-channel RCA connections with factory Bose installation.
