GM1A-RS Radio Replacement Interface

Introduction and Features

The GM1A-RS interface allows the replacement of a factory radio in select General Motors vehicles with the Class II Data-Bus. Using this interface will retain factory features such as steering wheel controls (SWC), rear seat controls, warning chimes, and the factory Bose amplifier when the original radio is removed. This interface also allows programming two radio functions to each SWC button using short press/long press dual command functionality. The GM1A-RS provides data bus driven outputs such as retained accessory power (RAP), vehicle speed signal (VSS), illumination, reverse trigger, and parking brake. Multiple camera inputs can be added to an aftermarket radio with Data-Bus controlled automatic activation (front camera only) by connecting a VS41 into the expansion port on the GM1A-RS.

Important Notes

• Does not retain OnStar.
• Does not provide RSE audio to aftermarket radio.
• Compatible with Premium (Y91 / UQ7) Bose, standard Bose (UQA), and non-amplified systems. Verify RPO code on a sticker in the glove compartment.
• Aftermarket radios with a 2-wire resistive SWC circuit require SWC programming per the radio's manual.
• The included chime speaker should be used for standard Bose systems, vehicles without a factory amplifier, or when connecting an aftermarket amplifier to cabin speakers.
• The [Programming Button] and [Adjustment Dial] on the side of the interface have multiple functions; see Page 2 for details.
• When used with the VS41 camera controller, the GM1A-RS provides Data-Bus controlled automatic activation for the front camera only. Refer to VS41 instructions for details.
• Fade is adjusted using the RadioPRO app. The GM1A-RS module must be connected to the vehicle and PC to adjust chime volume.
• In vehicles with Premium Bose (Y91 / UQ7), dynamic fade is only supported by GM1A-RT and GM1A-RST.
• In vehicles with Premium Bose (Y91 / UQ7), audio level can be fine-tuned using the [Adjustment Dial] on the interface (see Page 5). This adjustment does not operate with standard Bose Systems (UQA) or non-amplified systems.

Module Layout

Diagram description: The module layout shows several components. At the top are 'Radio Select [DIP Switches]'. Below that, on the left, is '[Interface Connector 1]' and '[Chime Connector]'. In the center are '[Adjustment Dial]' and '[Programming Button]'. On the right are '[LED 1]', '[LED 2]', '[USB Port]', and '[Expansion Port]'.

Installation Steps

Set DIP switches that correspond with your radio to the ON position. Set all other DIP switches to the OFF position.

DIP Switch Settings for Radio Brands:

*Other brands include Dual / Axxera, Jensen, Rockford Fosgate.

1. Set the Radio Select [DIP Switches] according to the radio you are installing.
2. Wire your aftermarket radio to the GM1A-RS's harness according to the wiring connections chart on the next page.
3. Plug [Interface Connector 1] and [Interface Connector 2] into the appropriate port on the GM1A-RS interface (using the illustration above or the label on the bottom of the interface).
4. Plug [Interface Connector 3] into the LOC-1 module. Connection will be dependent upon whether or not the vehicle has a factory amplified system. Plug this connector into the appropriate port on the included line output converter (Part # LOC-1; using the illustration on the next page or the text stamped into the housing). Improper connection will result in either very over-driven audio in amplified systems or very low audio in non-amplified systems. If this occurs, disconnect the harness from the LOC-1 Module and connect it into the port on the opposite side of the LOC-1.

Wiring Connections

A table details the wiring harness connections for the GM1A-RS.

Diagram description: Shows [Interface Connector 1], [Interface Connector 2], and [Interface Connector 3]. [Interface Connector 1] and [Interface Connector 2] are labeled 'Amplified' and 'Non-Amplified' respectively. [Interface Connector 3] is labeled '[Chime Speaker]'. Also shows '[Vehicle Connector 1]' and 'Line Output Converter (LOC-1)'.

VS41 Wiring

The VS41 camera switcher can connect to the GM1A-RS. Refer to separate instructions for wiring the VS41 into 2003-2006 Chevy/GMC Trucks and SUVs.

Adjustable Settings

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

Programming Button and Adjustment Dial Functions

Press and hold the [Programming Button] to access modes. [LED 2] indicates the mode.

Programming Modes:

• 1 Chime + [LED 2] flash green: SWC Re-assignment. Allows re-assigning SWC functions. Refer to Optional Steering Wheel Control Programming instructions.
• 2 Chimes + [LED 2] flash amber: SWC Re-calibration (Corvette only). Recalibrates analog SWC. Skipped if data control SWC are detected.
• 3 Chimes + Both [LEDs] flash green: Chime Volume Adjustment. Adjusts chime volume using the [Adjustment Dial]. Not available for Premium Bose (Y91/UQ7) systems.
• 4 Chimes + [LED 2] flash red: Master Reset. Resets interface to factory defaults for SWC Mapping, SWC Calibration, Camera Settings, Infotainment Settings, and Interface User Options.

Note: This process requires the interface to be in the vehicle with the key in the ignition position. For Premium Bose systems with aftermarket amplifiers, ensure the chime speaker is connected.

Default Steering Wheel Control Programming

Default SWC Button Assignments are provided for various radio brands, including specific assignments for Corvettes.

Default SWC Button Assignments (General):

Default SWC Button Assignments (Corvette):

Optional Steering Wheel Control Programming

Detailed steps for programming SWC functions. Includes a table for the optional programming order for various radio brands.

Programming Steps:

1. Turn key to ignition position.
2. Press and release [Programming Button].
3. Within 7 seconds, press the desired SWC button. Release within 1.5 seconds for short press, or hold until [LED 2] blinks for long press.
4. Repeat for each function.
5. Press and release [Programming Button] to skip a function.
6. Wait 7 seconds for programming to end.
7. Test functionality.
8. Repeat steps if any function does not work.

Optional Programming Order:

* Advent, Boyo, Dual, Lightning Audio, Jensen, Rockford Fosgate & Visteon. ** Jensen & Advent ONLY. *** XAV-AX100 Only.

Note: On any entry with multiple commands, the commands shown are source dependent.

SWC Re-calibration Procedure (Corvette Only)

Note: This is only necessary if after installation, the SWC are acting erratic or unresponsive in the Corvette.

1. Turn the key to the ignition position.
2. Press and hold the [Programming Button] until [LED 2] turns amber and two chimes are heard. Release button.
3. Within 7 seconds, press and hold the SWC button to be learned. The [LED] will turn off when the button is pressed and begin blinking when the value has been learned. Once the [LED] begins blinking, release the button.
4. Repeat step 3 for each additional function on the steering wheel.
5. If you come to a button in the list that your vehicle does not have, skip it by pressing the [Programming Button] on the interface. Any buttons not learned during this process will not function.
6. Once programming is completed, the [LED] will flash indicating end of programming.
7. Test the interface for proper functionality. Whenever a SWC is pressed, [LED 2] on the interface should blink green. If any function does not work, repeat the programming steps.

Button Programming Order:

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

Testing and Verification

1. Turn the ignition on. [LED 2] will illuminate red and the +12v accessory wire will turn on.
2. Turn on the radio and check chimes, volume, and balance. Note: Premium Bose Systems (Y91 / UQ7) will not fade from the aftermarket radio. If you want to adjust the fader, you must use the RadioPRO app. Please see the RadioPRO app section, at the bottom of this page, for more details.
3. In vehicles equipped with Premium Bose (Y91 / UQ7): If the overall volume is too low, use the [Adjustment Dial] on the side of the interface to set it to the desired level. The best way to do this is to turn the volume on the radio to 3/4 volume, then turn the [Adjustment Dial] on the GM1A-RS clockwise until some distortion is heard, then counter-clockwise a little.
4. Verify that all SWC buttons are functioning properly. If you are installing the GM1A-RS into a Corvette and are experiencing erratic SWC behavior, you may need to follow the SWC re-calibration procedure in the next section.
5. Turn off vehicle and remove key. RAP will be active and keep the radio on for 10 minutes or until any door is opened.
6. [LED 2] and the radio will turn off when RAP turns off.

Rear Seat Entertainment (RSE); If equipped

The factory RSE system will function independently from the aftermarket radio. The unit will power up and pass audio through the headphones as long as the vehicle's ignition is on. Audio from the RSE cannot be passed to the aftermarket radio when using the GM1A-RS. If you wish to pass audio to the aftermarket radio, you must use the GM1A-RT or GM1A-RST.

RadioPRO App

The RadioPRO app allows configuration of various settings and firmware updates.

Features:

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

*Available only in vehicles equipped with a Bose Smart Amplifier.

PLEASE NOTE:

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

Infotainment/Factory Amplifier Adjustments:

The RadioPRO app will also allow you to adjust the settings of the factory amplifier (Y91 / UQ7 Premium systems only). You can adjust Amp Gain, Fader, Balance, Bass, Mid, and Treble. When real-time fade is enabled in amplified systems, it will allow fading to be controlled directly from the aftermarket radio. Restoring factory settings on the module will default all values back to middle.

Diagram description: Two screenshots of the PAC RadioPRO application are shown. The left shows settings for 'Camera Settings' and 'Interface User Options', with a slider for 'Chime Volume'. The right shows settings for 'Gain', 'Fade', 'Bal', 'Treble', 'Mid', and 'Bass'.

Product Updates (Firmware)

Firmware Updates

The RadioPRO app will also allow you to update the interface with new firmware as it becomes available. The GM1A-RS can be updated with new firmware as it becomes available.

Update Process:

1. If this is the first time using the RadioPRO PC Application, download the Radio PRO PC Application. This can be found at the "Download" tab at the very bottom of the firmware list on this page.
2. Download the firmware file.
3. Install the Radio PRO PC Application using the .exe file you downloaded in step one.
4. Open the RadioPRO PC Application using the new shortcut created on your desktop.
5. Connect the interface to the computer using a standard to micro USB cable.
6. Click the "Firmware" icon.
7. Click "Select File” and browse to the new firmware file. The new firmware can be found where you saved it before beginning.
8. Once the file is chosen the update will begin. When successful it will show the text "Update Completed".

Diagram description: Two screenshots related to firmware updates. The left shows the RadioPRO application with options like 'Configure', 'Firmware', 'About', 'Support', and 'Update Firmware'. The right shows a file explorer window with a firmware file selected.

VS41 Camera Switcher

The VS41 is an intelligent 4-camera switcher for controlling front, rear, and blind spot cameras, designed to be used with PAC radio replacement interfaces. It is compatible with 2003-2006 GM Trucks/SUVs.

Key Features & Notes:

• These instructions are specifically for adding reverse, blind spot, and front cameras (or any combination of the three) to an aftermarket radio in 2003-2006 GM Trucks / SUVs.
• You must locate and connect to the analog turn signal wires in the vehicle, as well as connect the reverse output trigger from the GM1A to the VS41. Wire the VS41's analog input triggers 1, 3 and 4 according to the instructions below.
• Analog input trigger 2 on the VS41 only needs to be connected if you want manual activation of the front camera via toggle switch. Automatic activation of the front camera (Input 2) via Class II Data-Bus commands can be set using the RadioPRO PC application. See page 2 for more details on the RadioPRO PC app.
• The reverse trigger output will provide a 150 mA 12v (+) trigger while any of the input triggers are activated.
• The VS41 video output will always default to the signal from Input 1 when none of the input triggers are activated. This Input is ideal for connecting the rear (reverse) camera.
• The VS41 inputs have priority in descending numerical order. For example: If you have Input 3 or 4 triggered, then you trigger a lower number input (for example Input 2), Input 2 will take priority over the higher numbered Input.
• If there is poor video quality after installation of this module, please ensure quality connections on all RCA connections.

Wiring Connection Chart:

Note: *Please verify all signals with a multi-meter before connecting the VS41.

Installation Steps:

1. Connect the 10-pin expansion plug to the GM1A interface.
2. Wire up all the triggers and inputs as indicated in the chart on page 1.
3. See diagrams below for location of turn signal wires.
4. Once connected, verify all cameras are showing properly. The front camera behavior can be setup using the RadioPRO app. Please see the next section for more details on the RadioPRO app.

RadioPRO App for VS41:

Use of the RadioPRO App allows you to do the following: Set the behavior of the front camera.

Connect the GM1A interface to the PC and select the behavior of the front camera. Use the chart below to understand how each mode works. The GM1A does not have to be connected to power or in the vehicle to access camera settings.

Diagram description: Figure A shows turn signal wires. Figure B shows right and left turn signal wires.