GM1A-R Radio Replacement Interface

Introduction and Features

The GM1A-R interface allows the replacement of a factory radio in select General Motors vehicles equipped with the Class II Data-Bus. This interface retains factory features such as warning chimes and the factory Bose amplifier when the original radio is removed. The GM1A-R provides data-bus driven outputs including retained accessory power (RAP), vehicle speed signal (VSS), illumination, reverse trigger, and parking brake. It also offers an SWI Direct output for adding an optional PAC Steering Wheel Control (SWC) retention interface (SWI-RC or SWI-CP2). Rear Seat Controls (RSC), if equipped, will also be retained when used with the SWI interface.

Important Notes

• Does not retain OnStar.
• Does not provide RSE audio to the aftermarket radio.
• Compatible with both Premium (Y91 / UQA) and Standard Bose systems.
• The Programming Button and Adjustment Dial on the side of the interface have multiple functions. Refer to Page 2 for more details.

Module Layout

The module layout diagram illustrates the interface's components:

• LED 1: Indicator light.
• LED 2: Indicator light.
• Interface Connector 2: Port for connection.
• Interface Connector 1: Port for connection.
• Adjustment Dial: For adjusting settings.
• Programming Button: For accessing programming modes.
• USB Port: For PC connectivity.

Installation Steps

1. Wire your aftermarket radio to the GM1A-R's harness according to the wiring connections chart. For vehicles without a Bose system, cut off the resistor packs wrapped in heat shrink and connect the aftermarket radio's speaker outputs to the remaining wires as per the chart. For vehicles with a Bose system, wire the GM1A-R harness as-is, keeping the resistor packs in the harness.
2. Plug Interface Connectors 1 and 2 into the appropriate ports on the GM1A-R interface, using the illustrations or labels on the interface for guidance.
3. If installing an optional SWC interface with the GM1A-R, connect the SWI Direct Connector to the SWC interface. Refer to the SWC interface instructions for configuration and programming details.
4. Remove the factory radio and plug the GM1A-R's vehicle harness into the factory vehicle harness.
5. If necessary, program the SWC interface. Refer to the next section for programming instructions.

Wiring Connections

The interface includes Interface Connector 1, Interface Connector 2, and a Vehicle Connector for wiring.

SWI-DIRECT Steering Wheel Control Output Connector

The GM1A-R features a SWC output connector labeled "Connect to PAC Steering Wheel Control Interface" (refer to Figure A). All necessary connections are pre-made for ease of installation.

You can use either a PAC SWI-RC or an SWI-CP2 (sold separately).

• Using SWI-RC: Keep the loop on the output connector intact. Set the SWI-RC to version two and program the buttons according to the SWI-RC instructions.
• Using SWI-CP2: Utilize the DIP switch settings for the GM1A-R provided in the ControlPRO application. Steering wheel controls are preconfigured for the vehicle and radio but can be customized via the ControlPRO application. The loop on the output connector should remain intact.

Figure A shows the SWI-DIRECT Steering Wheel Control Output Connector.

Steering Wheel Control Button Reference

The following buttons are commonly programmable for steering wheel controls:

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

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. The table below outlines available settings:

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

Press and hold the programming button on the interface to access different programming modes. Release the button immediately once the desired mode's LED indicator is lit.

PLEASE NOTE:

• This process requires the interface to be in the vehicle with the ignition in the ON position.
• For Premium Bose systems (Y91 / UQA) with an aftermarket amplifier on cabin speakers, ensure the chime speaker is connected before proceeding. Refer to the RadioPRO app section on Page 3 for details.

Programming Modes:

• Mode A (2 Chimes and LED1 flash amber): SWC re-calibration (Corvette only). This mode allows re-calibration of analog SWCs if they are not functioning properly. It is automatically skipped if data control SWCs are detected.
• Mode B (3 Chimes and both LEDs flash green): Chime volume adjustment. Use the adjustment dial to set chime volume. This mode is not available for vehicles with Premium Bose (Y91 / UQA) amps, as the factory amp generates the chimes. Consult the vehicle's owner's manual for chime volume adjustments in those cases.
• Mode C (4 Chimes and LED 1 flash red): Master reset. Resets SWC Calibration, Infotainment Settings, and Interface User Options to factory defaults. LED 1 will flash red, and four chimes will be heard.

Testing and Verification

1. Turn the ignition ON. LED 1 will illuminate red, and the +12v accessory output will turn on.
2. Turn the radio ON and check chimes, volume, and balance. Note: Premium Bose Systems (Y91 / UQA) do not fade from the aftermarket radio. For fader adjustment, use the RadioPRO app (available at http://aampglobal.com/RadioProApp). See the RadioPRO app section for details.
3. For vehicles with Premium Bose (Y91 / UQA): If overall volume is too low, use the adjustment dial on the interface. For best results, set the radio volume to 3/4, turn the interface dial clockwise until slight distortion is heard, then turn it counter-clockwise slightly.
4. Chime Volume: If chime volume is too low, adjust using the procedure in the previous section or via the RadioPRO app.
5. If an SWI interface was installed, verify all SWC buttons function correctly. For Corvettes experiencing erratic SWC behavior, the SWC re-calibration procedure may be necessary.
6. Turn the vehicle OFF and remove the key. RAP will keep the accessory output ON for 10 minutes or until any door is opened.
7. LED 1 and the accessory output will turn OFF when RAP turns off.

SWC Re-calibration Procedure (Corvette Only)

Please Note: This procedure is only necessary if SWCs are acting erratically or are 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 programming button.
3. Within 7 seconds, press and hold the steering wheel button to be learned. The LED will turn off when pressed and begin blinking when the value is learned. Release the button once it blinks.
4. Repeat step 3 for each additional steering wheel function.
5. If a button is not present on your vehicle's steering wheel, skip it by pressing the interface's programming button. Buttons not learned 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 any function fails, repeat the programming steps.

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-R. For RSE audio to the aftermarket radio, use the GM1A-RT or GM1A-RST models.

RadioPRO App

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

The RadioPRO App allows you to:

• Configure User Interface Options:
  • Factory amplifier settings (Bass, Mid, Treble, Gain, Fader, and Balance)
  • Chime Volume
• 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
• Firmware Updates
• Reading firmware/hardware versions

Infotainment/Factory Amplifier Adjustments

The RadioPRO app enables adjustments for the factory amplifier in Y91 / UQA Premium systems. You can modify Amp Gain, Fader, Balance, Bass, Mid, and Treble. Restoring factory settings on the module will revert all values to their defaults.

Product Updates (Firmware)

The RadioPRO app allows you to update the interface with new firmware as it becomes available. Visit www.PAC-audio.com/firmware for available updates.

To update firmware:

1. Connect the interface to your PC.
2. Select "Firmware", then "Update Firmware".
3. Select "Select File" and browse to the saved firmware file.
4. The update process will begin. Once completed, disconnect the interface from the PC and test operation.

Technical Support

Email: support@PAC-audio.com

Phone: 866-931-8021

International: 727-572-9255 ext 230