PAC Audio GM1A-RST User Manual
Radio Replacement Interface with
GM1A-RST
Steering Wheel Control and Telematics Retention
for select General Motors Vehicles
with Class II Data-Bus
Introduction and Features
The GM1A-RST 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 Control (RSC), OnStar, warning
chimes and the factory Bose amplier when the original radio is removed. The GM1A-RST provides data bus driven outputs such
as retained accessory power (RAP), vehicle speed signal (VSS), illumination, reverse trigger and parking brake. You can also add
multiple camera inputs to your aftermarket radio with Data-Bus controlled automatic activation (front camera only) by connecting
a VS41 into the expansion port on the GM1A-RST.
Important Notes
1. The included chime speaker should be used when: The vehicle has a standard Bose system (UQ7), the vehicle does not have
a factory amplier at all, or if you are connecting an aftermarket amplier to the cabin speakers.
2. The Programming Button and Adjustment Dial on the side of the interface have multiple functions. Please see Page 3 for
more details.
3. Aftermarket radios with a 2-wire resistive based SWC circuit will not have default button assignments programmed. Please
refer to the owners manual of the radio you are installing to nd out the proper SWC programming procedure.
4. Compatible in both Premium Bose (Y91 / UQA) and Standard Bose systems.
5. Real time speaker fading on Premium factory amplied systems (Y91 / UQA) is only supported with the “amplied output”
connection of the GM1A-RST.
6. When using real time speaker fading (Premium Bose only), if the fader setting is biased more to the front or rear, as the radio
turns on the sound may begin at the default setting and then quickly transition to your custom setting.
7. Aftermarket radio features such as High Pass Filters (crossovers), DSP or “Network Mode” will interfere with proper fader
function (Premium Bose only). In order for the GM1A-RST’s fader function to work, the audio from the aftermarket radio’s
output must match so it can compare the front and rear audio levels and determine the proper fader setting for the factory
amplier.
8. When used in conjunction with the add on camera controller (VS41) the GM1A-RST will only provide Data-Bus controlled
automatic activation for the front camera. Please refer to the vehicle specic VS41 instructions for more detail.
Module Layout
Interface Connector 4
Expansion Port
Adjustment Dial Programming Button
USB PortRadio Select
DIP switches
Non-Amplied
Audio Output
Audio Output
Amplied
LED 1
LED 2
Interface Connector 1
© 2018 AAMP Global. All rights reserved. PAC is a Power Brand of AAMP Global.
Interface Connector 2 Interface Connector 3
PAC-audio.com
Rev: V6
Date: 100318
Page 1
Radio Replacement Interface with
GM1A-RST
Steering Wheel Control and Telematics Retention
for select General Motors Vehicles
with Class II Data-Bus
Installation Steps
Set DIP switches that correspond with your radio to the ON position.
Set all other DIP switches to the OFF position.
Alpine JVC
1 2 1 & 2 3 2 & 3 1, 2, & 3 4 1 & 4
Other =
*Other - Dual / Axxera (these brands could also have 2-wire resistive), Jensen, Rockford Fosgate
Advent, BOYO, Dual, Lightning Audio, Rockford Fosgate, Visteon
Kenwood /
Lightning Audio
1. Set the Radio Select DIP switches according to the radio you are installing.
2. Wire your aftermarket radio to the GM1A-RST’s harness according to the wiring connections chart below.
3. The Brown mute loop in Interface Connector 4 (if not cut) will turn the GM1A’s accessory output off when any OnStar
function is active. If the aftermarket radio has a mute input, cut this loop and connect the Brown wire in pin 23 to it.
4. Plug Interface Connectors 1 and 2 into the appropriate ports on the GM1A-RST interface (using the diagram on page 1 or
the label on the bottom of the interface).
5. The Connector 3 connection will be dependent upon whether or not the vehicle has a factory amplied system. Plug this
connector into the appropriate port on the GM1A-RST (using the diagram on page 1 or the label on the bottom of the
interface).
6. If the aftermarket radio is equipped with an auxiliary input and you wish to retain the factory RSE audio, plug the RCA
connectors from the secondary harness into the radios auxiliary input.
7. Remove the factory radio and plug in the GM1A-RST’s Vehicle Connector 1 and Vehicle Connector 2 into the factory vehicle
harness.
8. If you wish to reassign functions to the SWC, follow the programming instructions on Page 4.
9. If you are connecting an aftermarket amplier to the cabin speakers, connect the chime speaker to the chime plug coming out
of Interface Connector 4 and install the chime speaker in a place free of obstructions, where it can be easily heard (usually
low in the dash facing downward).
Clarion /
Nakamichi
2-Wire
Resistive
Pioneer /
Other*
Sony Fusion
Interface Connector 1
(3-pin)
Interface Connector 4
(24-pin)
Interface Connector 2
(20-pin)
Vehicle Connector 1
(24-pin)
Interface Connector 3
(12-pin)
Vehicle Connector 2
(12-pin)
Wiring Connections
Yellow 12v+
Red
Black Ground
Brown Loop Mute Output
Blue Not Used
Blue / White Remote On Input
Orange Not Used
Orange / White Illumination Output
Purple / White Reverse Output (+)
Light Green Parking Brake Output (-)
Pink Vehicle Speed Signal
Blue / Yellow SWC Output / Key 1
Brown SWC Output / Key 2
3.5 mm Jack SWC Output
Purple Rear R + input
Purple / Black Rear R - input
Green Rear L + input
Green / Black Rear L - input
Gray Front R + input
Gray / Black Front R - input
White Front L + input
White / Black Front L - input
Accessory Output
(10 amp)
(VSS) Output
© 2018 AAMP Global. All rights reserved. PAC is a Power Brand of AAMP Global.
PAC-audio.com
Rev: V6
Date: 100318
Page 2
Radio Replacement Interface with
AVAILABLE ON PC APP
GM1A-RST
Steering Wheel Control and Telematics Retention
for select General Motors Vehicles
with Class II Data-Bus
VS41 Wiring
The VS41 can be connected to the GM1A-RST and used to switch multiple cameras. Please refer to the document labeled
“Instructions for wiring the VS41 into 2003-2006 Chevy / GMC Trucks and SUVs” which can be found on www.pac-audio.
com under the VS41 product page.
Adjustable Settings
These products have settings that are adjustable through our RadioPRO PC app or through the push-button on the module.
Some settings are only adjustable through the PC app. Some of these settings require the module to be connected to the
vehicle. Below is a breakdown of these settings.
CONNECTED TO CAR NOT CONNECTED TO CAR
Chime volume (excluding Premium Bose Y91/UQA) YES NO YES
Factory amplifier settings:
Bass, Mid, Treble, Gain, and Fade
(Premium Bose Y91/UQA only)
OnStar volume (RST or RT products only) YES NO YES
Read product version YES YES N/A
Update firmware YES YES N/A
Camera settings (VS41 required) YES YES NO
Related Downloads
• RadioPRO PC App: http://aampglobal.com/radioproapp
• Latest instruction manuals: Search part number on pac-audio.com, and then look under the “Downloads” tab
YES NO GAIN ONLY
AVAILABLE ON MODULESETTING
Programming Button and Adjustment Dial Functions
You can press and hold the programming button on the side of the interface to access different programming modes. Once the
LED is lit to the mode you desire (see below for modes), immediately release the programming button to access that mode.
PLEASE NOTE:
• This process must be done with the interface in the vehicle and the key in the ignition position.
• If there is a Premium Bose system, and you are also installing an amplier on the cabin speakers, make sure that
the chime speaker is connected and chimes are enabled through the RadioPRO app before proceeding. Please see
the RadioPRO app section on Page 4 for more details.
A. 1 Chime and LED 1 ash green: SWC re-assignment. This allows you to re-assign the SWC functions to the buttons
of your choice. Please see the Optional Steering Wheel Control Programming instructions on Page 4 for more details.
B. 2 Chimes and LED1 ash amber: SWC re-calibration (this mode is available in the Corvette only).This allows you to
re-calibrate the analog SWC in the event they fall out of the expected range and do not function properly. If data control
SWC are detected by the interface, this mode will be automatically skipped.
C. 3 Chimes and both LEDs ash green: Chime volume adjustment. This allows you to adjust the volume of the
chimes generated by the interface using the adjustment dial on the side. (This mode is not available in vehicles
equipped with Premium Bose (Y91 / UQA) amps. If a premium Bose amp is detected by the interface, this mode will be
skipped as the factory amp is what generates the chimes. Please see the vehicles owner’s manual for adjustment of
chime volume in vehicles with Premium Bose (Y91 / UQA).
D. 4 Chimes and LED 1 ash red: Master reset. This does a master reset of the interface and restores the following
settings to factory defaults:
• SWC Mapping
• SWC Calibration
• Camera Settings
• Infotainment Settings
• Interface User Options
© 2018 AAMP Global. All rights reserved. PAC is a Power Brand of AAMP Global.
PAC-audio.com
Rev: V6
Date: 100318
Page 3
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