Metra - AXGM-08 - OnStar Class II Interface

The Metra AXGM-08 OnStar Class II Interface is a vehicle-specific data integration module designed for select GM vehicles equipped with Class II data networks and factory amplified audio systems. This interface provides the necessary accessory power and vehicle signal outputs to support aftermarket head unit installations while retaining essential OEM features such as OnStar and factory Bluetooth connectivity, chimes, and audio balance/fade control. Built for professional installers, the AXGM-08 ensures a clean transition from factory radios to aftermarket systems without sacrificing key vehicle functions.

KEY BENEFITS

• Supplies regulated 12 V DC accessory power (10 A) to support aftermarket head unit operation
• Retains Retained Accessory Power (R.A.P.) for consistent accessory behavior after the factory radio is replaced
• Retains factory warning chimes and allows adjustable gain control for chime and OnStar audio levels
• Provides navigation-related signal outputs including parking brake, reverse, mute, and vehicle speed sense
• Maintains OEM OnStar and factory Bluetooth connectivity (where equipped) for retained functionality
• Accepts high-level speaker input for integration with amplified systems
• USB updatable firmware allows future interface improvements or expanded vehicle support
• Ideal for professional installers upgrading radios while preserving vehicle systems

TECHNICAL SPECIFICATIONS

• Weight: N/A
• Dimensions: 7.50″ L × 3.00″ W × 2.50″ H (module footprint)
• Application: Select GM vehicles with Class II data networks and amplified systems
• Function: OnStar Class II data interface with accessory power and vehicle signal outputs
• Accessory Power Output: 12 V DC, 10 A
• Retained Functions: Retained Accessory Power, warning chimes, balance/fade control
• Navigation/Vehicle Outputs: Parking brake, reverse, mute, vehicle speed sense
• Connectivity Retained: OnStar and OEM Bluetooth
• Speaker Input: High-level input for amplified factory systems
• Firmware Updates: USB updatable
• Housing: Black interface module

INSTALLATION & COMPATIBILITY

The AXGM-08 installs inline between the aftermarket head unit and factory wiring harness in compatible GM vehicles equipped with OnStar Class II networks and amplified factory audio. It supplies the required accessory power and data signals for proper aftermarket radio operation while retaining key factory features and connectivity. This interface is best suited for professional installations where preserving OnStar functions, Bluetooth connectivity, and chime behavior is essential. Compatibility should be confirmed for the specific model and year before installation.

FAQS

• What does the AXGM-08 interface do?
  AXGM-08 is a GM radio replacement interface that provides accessory power, retained accessory power, and warning chimes when installing an aftermarket head unit.
• Which vehicles typically require the AXGM-08?
  AXGM-08 supports select GM vehicles with data-controlled electrical systems. Compatibility depends on model year and factory configuration, so checking fitment is critical.
• How does AXGM-08 improve installation reliability?
  It eliminates hardwiring guesswork by handling digital signals properly, reducing electrical issues and ensuring consistent radio operation after installation.
• Is AXGM-08 suitable for DIY installers?
  Experienced DIY installers can use it successfully, but professional installation is recommended to ensure all data connections and retained features work correctly.