GM1A-RX

Introduction and Features

The GM1A-RX interface facilitates the replacement of factory radios in select General Motors vehicles equipped with the Class II Data-Bus. It preserves essential factory features like warning chimes and the factory Bose amplifier after the original radio is removed. The GM1A-RX provides data bus outputs including Retained Accessory Power (RAP), Vehicle Speed Signal (VSS), illumination, reverse trigger, and parking brake. It also offers an SWI Direct output for integrating optional PAC Steering Wheel Control (SWC) retention interfaces (SWI-RC or SWI-CP2). Rear Seat Controls (RSC), if present, can also be retained using the SWI interface. Additionally, multiple camera inputs can be added to an aftermarket radio with data bus-controlled automatic activation (front camera only) by connecting a VS41 unit to the GM1A-RX's expansion port.

Important Notes

• Does not retain OnStar.
• Does not provide RSE audio to the aftermarket radio.
• Compatible with both Premium (Y91 / UQA) and Standard systems.
• The included chime speaker should be used when: the vehicle has a standard Bose system (UQ7), the vehicle lacks a factory amplifier, or an aftermarket amplifier is connected to the cabin speakers.
• The Programming Button and Adjustment Dial on the interface have multiple functions. Refer to Page 2 for details.
• When used with the VS41 camera controller, the GM1A-RX provides data bus controlled automatic activation only for the front camera. Consult VS41-specific instructions for more details.
• Audio fade is adjusted via the RadioPRO app, accessible at https://aampglobal.com/RadioProApp. The GM1A-RX module must be connected to the vehicle and PC to adjust chime volume.
• Dynamic fade is supported only by the GM1A-RT and GM1A-RST in vehicles with Premium Bose (Y91 / UQA).

Module Layout

The interface module features the following connectors and controls:

• Interface Connector 1
• Interface Connector 2
• Chime Connector
• LED 1
• LED 2
• Adjustment Dial
• Programming Button
• USB Port
• Expansion Port

Installation Steps

1. Connect your aftermarket radio's harness to the GM1A-RX harness as per the wiring connections chart.
2. Plug Interface Connectors 1 and 2 into their respective ports on the GM1A-RX interface.
3. Connect Interface Connector 3 to the LOC-1 module. The connection point depends on whether the vehicle has a factory amplified system. Connect to the appropriate port on the included line output converter (Part # LOC-1). Incorrect connection may result in over-driven or very low audio. If this occurs, switch the connector to the other port on the LOC-1 module; the remaining connector will be unused.
4. If installing an optional SWC interface, connect the SWI Direct Connector to the SWC interface.
5. Remove the factory radio and connect the GM1A-RX's vehicle harness to the factory vehicle harness.
6. If required, program the SWC interface. Refer to the next section for programming details.
7. For vehicles with a standard Bose system, no factory amplifier, or when connecting an aftermarket amplifier to cabin speakers, connect the chime speaker to the interface's chime connector. Install the chime speaker in an unobstructed location where it can be easily heard, typically low in the dash facing downward.

Wiring Connections

Steering Wheel Control Output Connector

The GM1A-RX includes an SWC output connector labeled "Connect to PAC Steering Wheel Control Interface" (Fig. A). Connections are pre-made for ease of installation.

Compatibility:

• PAC SWI-RC or SWI-CP2 (sold separately).
• For SWI-RC: Keep the loop on the output connector intact. Set SWI-RC to version two and follow its programming instructions.
• For SWI-CP2: Use DIP switch settings from the ControlPRO application specific to the GM1A-RX. Steering wheel controls are preconfigured but can be customized via the ControlPRO application. The loop on the output connector should remain intact.

VS41 Wiring

The VS41 can be connected to the GM1A-RX to manage multiple cameras. Refer to the document "Instructions for wiring the VS41 into 2003-2006 Chevy / GMC Trucks and SUVs" available at www.pac-audio.com under the VS41 product page.

Adjustable Settings

Settings can be adjusted via the RadioPRO PC app or the module's push-button. Some settings require the module to be connected to the vehicle.

Related Downloads

• RadioPRO PC App: https://aampglobal.com/RadioProApp
• Latest instruction manuals: Search part number on pac-audio.com and navigate to the "Downloads" tab.

Programming Button and Adjustment Dial Functions

Access programming modes by pressing and holding the programming button. Release the button when the desired mode's LED indicator lights up.

Important Notes:

• Perform programming with the interface installed in the vehicle and the ignition key in the ON position.
• The chime speaker must be connected unless the vehicle has a Premium Bose (Y91 / UQA) system. If a Premium Bose system is present, cabin speakers must be connected to the Bose amplifier.
• If a Premium Bose system (Y91 / UQA) is present and an aftermarket amplifier is being installed for cabin speakers, ensure the chime speaker is connected before proceeding. Refer to the RadioPRO app section on Page 4 for more details.

Programming Modes:

• A. 2 Chimes and LED1 flash amber: SWC Re-calibration (Corvette only). Recalibrates analog SWCs if they fall outside expected ranges. This mode is skipped if data control SWCs are detected.
• B. 3 Chimes and both LEDs flash green: Chime Volume Adjustment. Adjusts chime volume using the adjustment dial. Not available for vehicles with Premium Bose (Y91 / UQA) amps; chime volume is managed by the factory amp.
• C. 4 Chimes and LED 1 flash red: Master Reset. Resets the interface to factory defaults, including SWC Calibration, Camera Settings, Infotainment Settings, and Interface User Options.

Testing and Verification

1. Turn the ignition ON. LED 1 should illuminate red, and the +12v accessory output should activate.
2. Turn on the radio and verify chimes, volume, and balance. Note: Premium Bose Systems (UQA / Y91) do not support fader control from the aftermarket radio. For fader adjustments, use the RadioPRO app (https://aampglobal.com/RadioProApp).
3. For vehicles with Premium Bose (Y91 / UQA): If overall volume is low, use the adjustment dial to set the desired level. A recommended method is to set the radio volume to 3/4, turn the GM1A-RX adjustment dial clockwise until slight distortion occurs, then turn it back slightly counter-clockwise.
4. Chime Volume: If chime volume is too low, adjust using the procedure in section B above or via the RadioPRO app.
5. If an SWI interface was installed, confirm all SWC buttons function correctly. For Corvettes experiencing erratic SWC behavior, follow the SWC re-calibration procedure.
6. Turn off the vehicle and remove the key. RAP will maintain accessory output for 10 minutes or until a door is opened.
7. LED 1 and the accessory output will turn off when RAP deactivates.

SWC Re-calibration Procedure (Corvette Only)

This procedure is necessary only if SWCs are erratic or unresponsive in a Corvette after installation.

1. Turn the key to the ignition position.
2. Press and hold the programming button until LED 1 turns amber and two chimes are heard. Release the button.
3. Within 7 seconds, press and hold the steering wheel button to be learned. The LED will turn off when pressed and blink when learned. Release the button.
4. Repeat step 3 for each additional steering wheel function.
5. Skip buttons not present on your vehicle by pressing the programming button. Unlearned buttons will not function.
6. Once programming is complete, the LED will flash to indicate the end of the process.
7. Test the interface for proper functionality. LED 1 should blink green when any SWC is pressed. If a function fails, repeat the programming steps.

Button Programming Order:

• Volume Up
• Volume Down
• Seek Up
• Seek Down
• Preset
• Answer / Voice
• Hang Up
• Preset Up

Rear Seat Entertainment (RSE): If equipped

The factory RSE system operates independently of the aftermarket radio. It powers up and passes audio through headphones when the vehicle ignition is on. Audio from the RSE cannot be routed to the aftermarket radio using the GM1A-RX. For RSE audio to the aftermarket radio, use the GM1A-RT or GM1A-RST.

RadioPRO App

Download the RadioPRO PC App at https://aampglobal.com/RadioProApp.

The RadioPRO App allows you to:

• Configure User Interface Options, including:
  • Factory amplifier settings (Bass, Mid, Treble, Gain, Fader, and Balance)
  • Chime Volume
  • Camera Settings
• Update Product Firmware
• Read Firmware/Hardware Versions

Please Note:

• The interface must be connected to the vehicle for the following RadioPRO App features:
  • Factory Amplifier Settings
  • Chime Volume
• The interface does not need to be connected to the vehicle for the following RadioPRO App features:
  • Interface User Options
  • Camera Settings
  • Firmware Updates
  • Reading firmware/hardware versions

Infotainment/Factory Amplifier Adjustments

The RadioPRO app also enables adjustments to factory amplifier settings (UQA / Y91 Premium systems only), including Amp Gain, Fader, Balance, Bass, Mid, and Treble. Restoring factory settings on the module will revert all values to their defaults.

Product Updates (Firmware)

Firmware Updates

The RadioPRO app facilitates updating the interface with new firmware as it becomes available. Visit www.PAC-audio.com/firmware for updates.

To update:

1. Connect the interface to your PC.
2. In the RadioPRO app, select "Firmware", then "Update Firmware".
3. Select "Select File".
4. Browse to and select the saved firmware file. The update process will begin.
5. Once complete, disconnect the interface from the PC and test its operation.

Technical Support

• Email: support@PAC-audio.com
• Phone: 866-931-8021
• International: 727-572-9255 ext 230