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Scosche GM21SR-open box

GM/LAN Amplified/Non-Amplified OnStar Integrated Harness for 2006-Up Select GM Vehicles

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Radio Replacement Interface for select GM / Chevrolet vehicles 2006-up. This Harness will allow you to retain Onstar, RAP & FACTORY AMPLIFIERS (Bose, Monsoon etc.). It is not included in our standard free harness offer when a head unit is purchased.

General Features:

  • Radio replacement interface
  • Designed for 2007-up GM vehicles with OnStar, RAP and Factory Amplifiers
  • This Product Retains the Following Factory Equipped Features:
    • Compatible with both non-Bose and Standard Bose
    • OnStar
    • Warning Chimes
    • Folding Mirrors (Including Reverse)
    • Park Assist (Front/Rear)
    • Heated Seats
    • AC Fan Speed
    • Turn Signal
  • Compatible with RAP systems (Retained Accessory Power)
  • 2007 GMC Yukon (WITH FACTORY AMPS)
  • 2007 Chevrolet Suburban (WITH FACTORY AMPS)
  • 2007 Chevrolet Tahoe (WITH FACTORY AMPS)
  • 2006-2007 Chevrolet Monte Carlo (WITH FACTORY AMPS)
  • 2006-2007 Chevrolet Impala (WITH FACTORY AMPS)
  • 2007 Chevrolet Avalanche (WITH FACTORY AMPS)
  • Retains OnStar functionality, warning chimes, and parking assist chimes.
  • Not compatible with Denali
  • NOTE: Not for use on Premium Bose Sound Systems, includes Y91/Z75 Bose. Code may be found in the service parts sticker (normally in glove box)
  • 1-year warranty

Harness Features

Vehicle Sound System
This refers to what kind of sound system the vehicle has. Premium audio systems are generally name brand systems (such as JBL, Bose, Rockford Fosgate, etc) that have been installed inside a vehicle when it leaves the factory. Often they more advanced systems, complex wiring, factory amplifiers, and other features that can make installing aftermarket component difficult.
Premium Sound
Main Harness Function
Different installations on different vehicles require different harnesses. This type is what the harness is considered. Each wiring harness we sell serves a purpose such as installing an aftermarket car stereo, integrating an aftermarket amplifier with your factory car stereo, connecting Bluetooth to your factory car stereo, and more.
Install a Car Stereo & Bypass the Factory OEM Amplifier
Additional Harness Features
The various features that the wiring harness provides to your car stereo and/or audio system.
Chime Retention
OnStar Retention
Retained Accessory Power (RAP) Retention
Compatible Vehicle Make
Allows you to view only items that are compatible with your vehicle's make. Does not guarantee that it will work with your vehicle year or model.
Compatible Vehicle Make and Model
The model of vehicle that this vehicle specific product is designed for. Please keep in mind that engine variations can affect the compatibility of the products.
Chevy Astro
Chevy Avalanche
Chevy Blazer
Chevy Cavalier
Chevy Corvette
Chevy Express Van
Chevy Impala
Chevy Lumina
Chevy Monte Carlo
Chevy Silverado
Chevy Suburban
Chevy Tahoe
GMC Canyon
GMC Envoy
GMC Savana
GMC Sierra
GMC Yukon

Premium Harness Features

Factory System Amplification
This refers to the factory sound system and whether the item is compatible with amplified or non-amplified systems.
Compatible Premium Audio Systems
Some vehicles have higher end audio systems installed in them by the manufacturer. This specifies which premium audio systems this item is compatible with.
Standard Bose
On-Star Compatible
This means that the harness is compatible with vehicles that have On-Star built-in.
CAN-BUS Compatible
CANBUS Ballasts ensure compatibility with ALL vehicle makes and models without the need for additional accessories. In addition, they have built-in Anti-Flickering Capacitors to help prevent lighting issues caused by voltage spikes and drops by stabilizing the power.
GM-LAN Compatible
This means that the item is compatible with GM-LAN systems.
Compatible with Aftermarket Navigation Systems
This means that the item is made to work with aftermarket systems with navigation. Typically, this means that the harness has wires that are used with GPS navigation systems, such as VSS wires and others. Please read the product description for full details of this feature.
Chime Retention
This means that the harness is able to retain the vehicles chimes.

Warranty and Return Policy

Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider

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Browse 2 questions and 4 answers
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Will this allow steering wheel controls to function as well?
2007 Chevy Suburban W/Bose W/OnStar
Quinton B on Sep 9, 2014
Best Answer: Hello Quinton,

No. You must also pick up the Axxess ASWC-1, Universal Steering Wheel Control Interface. For slightly easier installation, a bit of a price break, consider the PAC RadioPro RP4-GM31 instead; as it has SWC retention with It already.

[Note: If you are purchasing a Headunit WITH the harness, give our Sales Team a call to make the swap/accommodation]
Reply · Report · Customer SStaff on Sep 9, 2014
· Add Answer · I Have This Question Too (0)
I have a 2007 Chevrolet Avalanche with on-star, non-bose. I purchased this headunt and wanted to know if the Scosche GM21SR was compatible with maintaining my chimes and on-star functionality? I attempted to call customer support but could not get through.
Jacoby P on Nov 21, 2016
Scosche GM21SR
Scosche GM21SR
Pioneer AVH-X2800BS
Pioneer AVH-X2800BS
Best Answer: Yes, it is compatible. However, we suggest going with the Metra equivalent, the Axxess GMOS-LAN-01, because it is readily available (not special order).
Reply · Report · Rick MStaff on Nov 21, 2016
· Add Answer · I Have This Question Too (0)

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Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: Scosche GM21SR-open box