RP4-GM31 - Car audio interface PAC - Free user manual and instructions

Product Type	Radio Replacement Interface
Brand	PAC
Model	RP4-GM31
Compatible Vehicles	Select General Motors vehicles with 29-bit LAN radios
Retained Factory Features	Steering wheel controls, warning chimes, rear seat controls (RSC), BOSE amplifier
Outputs (Data Bus Driven)	Retained accessory power (RAP), vehicle speed sensor (VSS), illumination, reverse trigger, parking brake
Radio Select Switch	Rotary switch with positions for Alpine (1), JVC (2), Kenwood/Lightning Audio (3), Clarion/Nakamichi (4), Pioneer/Other (7), Sony (8), Fusion (9)
SWC Programming	Pre-programmed default functions; optional manual programming with short press/long press dual command
Firmware Update	Via PAC-UP interface updater (sold separately)
Input Voltage	12V DC (vehicle battery)
Wiring Connection Type	Color-coded wires for speaker, power, and SWC signals
Audio Compatibility	Works with BOSE amplified systems; requires line output converter (LOC) if aftermarket radio lacks low-level outputs
RAP Function	Keeps radio on for 10 minutes after ignition off or until driver's door opens
LED Indicator	Solid when powered; flashes on SWC press; flashes 3 times at end of programming
Programming Button	Located on side of interface; used to enter programming mode and skip functions
Default SWC Functions	Volume +/-, Source, Track +/-, Answer/Voice, Mute/End (varies by radio brand)
Vehicle Speed Output	Pink wire
Illumination Output	Orange/White wire (+12V)
Reverse Output	Purple/White wire (+12V)
Parking Brake Output	Light Green wire (ground)
Accessory Output	Red wire (10 amp max)
Antenna On Input	Blue wire
Amp Turn On Input	Blue/White wire
Included Components	Interface module, wiring harness with vehicle and interface connectors

Frequently Asked Questions - RP4-GM31 PAC

How do I set the radio select switch on the RP4-GM31?

Locate the rotary switch on the side of the interface. Rotate it to match your aftermarket radio brand according to the chart: 1=Alpine, 2=JVC, 3=Kenwood/Lightning Audio, 4=Clarion/Nakamichi, 7=Pioneer/Other*, 8=Sony, 9=Fusion. Do this before plugging the interface into the vehicle.

Can I use this interface with a factory BOSE amplified system?

Yes, but if your aftermarket radio does not have low-level RCA outputs, you should use a line output converter (LOC) such as the PAC LP5-4 or two LP5-2 to match the input voltage and prevent overdriven audio.

How do I program the steering wheel controls?

Turn the ignition on. Press and release the programming button on the side of the interface. Within 7 seconds, press the steering wheel button you want to program. For short press, release within 1.5 seconds; for long press, hold until LED blinks. Repeat for each function. To skip a function, press the programming button again. Wait 7 seconds for LED to flash 3 times to confirm end of programming.

What if my steering wheel does not have a particular function listed in the programming chart?

You can skip that function by pressing and releasing the programming button on the side of the interface once. The LED will flash off and on, indicating the function was skipped. Continue with the next function.

How do I restore the default steering wheel control settings?

Press and release the programming button on the side of the interface once. Wait 7 seconds for the LED to flash 4 times. This restores all default SWC assignments.

What is short press/long press dual command functionality?

This feature allows you to assign two aftermarket radio functions to a single steering wheel button. A quick press (<1.5 sec) triggers the short press command; pressing and holding (>2 sec) triggers the long press command. No long press commands are programmed by default.

My aftermarket radio has common ground RCA outputs. What should I do?

To prevent ground loop or engine noise, install a pair of ground loop isolators (e.g., PAC SNI-1 or LPGL-2) on the RCA outputs.

How do I update the firmware on the RP4-GM31?

Use the PAC-UP interface updater (sold separately). Visit www.PAC-audio.com/firmware to check for and download updates. Connect the PAC-UP to the interface and follow the instructions on the website.

What does the LED indicator mean during use?

When the ignition is on, the LED is solid, indicating power. It flashes whenever a steering wheel control button is pressed. During programming, it provides feedback: flash off/on for skip, flash 3 times for end of programming, flash 4 times for default restore.

How do I test that the installation is working correctly?

Turn ignition on: LED should come on and accessory wire should activate. Turn on radio and check balance/fade (note: factory amplified systems may not fade). Verify subwoofer (if equipped). Test all steering wheel controls. Turn off vehicle: RAP should keep radio on for 10 minutes or until driver's door opens, then LED and radio turn off.

USER MANUAL RP4-GM31 PAC

Introduction and Features

The RP4-GM31 interface allows the replacement of a factory radio in select General Motors vehicles with 29-bit LAN radios. Using this interface will retain factory features such as steering wheel controls (SWC), Warning Chimes, Rear Seat Controls (RSC) and the BOSE amplifier when the original radio is removed. Use of this interface also allows you to program two radio functions to each SWC button, by using short press / long press dual command functionality. The RP4-GM31 also provides data bus driven outputs such as retained accessory power (RAP), vehicle speed sensor (VSS), illumination, reverse trigger and parking brake.

Important Notes

1. These instructions only apply to R.1.2.3a.8 or later revisions. The revision info can be found on a small white sticker on the interface and packaging.
2. The radio select rotary switch on the side of the interface, must be adjusted to the proper radio setting before plugging the interface into the vehicle (see below for setting chart).
3. The interface comes pre-programmed for all of the vehicle's factory SWC functions and does not require programming, unless you wish to re-assign the SWC functions or utilize short press / long press dual command functionality. The SWC can always be restored to default settings by pressing and releasing the program button on the side of the interface once, and waiting 7 seconds for the LED to flash 4 times.
4. RSC buttons that are identical to the SWC will mimic the SWC one for one.
5. To prevent over driven audio when installing into a vehicle with a Bose system and the aftermarket radio does not have low level outputs, a 4 channel or two 2 channel LOC's are recommended to match the input voltage. We recommend the LP5-4 or two LP5-2 or any other LOC that have the same characteristics as the LP5-4 or LP5-2.
6. To prevent ground loop or engine noise when installing aftermarket radios that use a common ground on the RCA outputs, a pair of ground loop isolators (part # SNI-1 or LPGL-2) are required.
7. The LED will flash whenever a SWC button is pressed.

Wiring Connection Chart
Vehicle Connector

Yellow	Battery +12v
Black	Ground
Blue	Antenna On Input
White	Front Left + input
White / Black	Front Left - input
Gray	Front Right + input
Gray / Black	Front Right - input
Green	Rear Left + input
Green / Black	Rear Left - input
Purple	Rear Right + input
Purple / Black	Rear Right - input

Interface Connector

Light Green	Parking Brake Output (-)
Pink	Vehicle Speed Output
Blue / White	Amp Turn On Input
Red	Accessory Output (10 amp)
Orange / White	Illumination Output (+)
Purple / White	Reverse Output (+)

SWC Connector

Blue / Yellow	Kenwood, Newer JVC
3.5mm Jack	Alpine, JVC, Clarion, Fusion, Pioneer, Sony, Boyo, Dual, Lightning Audio, Visteon or Advent

Illustration / Schematic

Wiring SWC Connection

Installation Steps

SET RADIO SELECT SWITCH

Alpine	JVC	Kenwood / Lightning Audio	Clarion / Nakamichi	Pioneer / Other*	Sony	Fusion
1	2	3	4	7	8	9

*Other - Dual / Axxera, Jensen, Rockford Fosgate

1. The radio select rotary switch on the side of the interface must be adjusted to the proper radio setting before plugging the interface into the vehicle.
2. Make all connections as described in the chart on page 1.

If there is a Bose® Audio system present: Connect the RCA inputs to the aftermarket radios pre-amp output. The audio level will vary depending on the new radios pre-amp output voltage (2 - 4 volts is recommended).

If there is not a Bose® Audio system present: Cut the RCA inputs off and connect the aftermarket radios speaker outputs to the remaining wire according to the chart on page 1.

1. Connect the SWC wire according to the chart on page 1 (aftermarket radio MUST support a wired remote input).
2. If you wish to reassign functions to the SWC, follow the programming instructions discussed later on this page.

Default Steering Wheel Control Programming

IMPORTANT! The interface comes pre-programmed for the functions listed in the chart below and does not require programming unless you wish to re-assign the SWC functions to different buttons. The SWC can always be restored to default settings by pressing the program button on the side of the interface once and waiting for the timeout.

Default SWC Button Assignments

	Alpine JVC	Kenwood	Clarion Pi	Pioneer Sony	Fusion
Volume +	Volume +	Volume +	Volume +	Volume +	Volume +	Volume +
Volume -	Volume -	Volume -	Volume -	Volume -	Volume -	Volume -
Source	Source	Source	Source	Source	Source	Source	Source
Track +	Track +	Track +	Track +	Search +	Track +	Track +	Track +
Track -	Track -	Track -	Track -	Search -	Track -	Track -	Track -
Answer/Voice	Receive	Receive	Receive	Receive	Receive	Answer/End	N/P
Mute/End	Mute/End	Mute/End	Mute/End	Mute/End	Mute/End	Mute/End	Mute/End

Optional Steering Wheel Control Programming

If you wish to re-assign the SWC functions or utilize short press long press dual command functionality, the interface must be programmed in the specific order shown on the chart below. If you come across a function in the chart that your steering wheel does not have, or you do not want to program, press and release the programming button on the side of the interface to skip that function. The LED will flash off, and on confirming that you have successfully skipped that function and are ready to proceed to the next one.

Short Press Long Press Dual Command Functionality

This feature allows you to assign two aftermarket radio functions to each of the vehicles SWC buttons. It can be used with as many of the buttons as the user likes or none at all. When this functionality is implemented, quickly pressing and releasing a SWC button will initiate the short press command while pressing and holding a SWC button for longer than two seconds, will initiate the long press command. Please note that no long press commands are programmed by default. If you wish to assign dual command functionality to the SWC, please follow the programming steps on the next page.

Optional Steering Wheel Control Programming (cont.)

Optional Programming Order

	Alpine JVC Kenwood Clarion Other * Pioneer Sony Fusion
1 Volume -	Volume + Volume +	Volume + Volume +	Volume + Volume +	Volume +
2	Volume -	Volume -	Volume -	Volume -	Volume -	Volume -	Volume -	Volume -
3 Mute	Mute		ATT	Mute	Mute	Mute	Mute	Mute
4	Preset +	Source	Source	Source	Preset +	Preset +	Preset +	Source
5	Preset -	Track +	Play	Search +	Preset -	Preset -	Preset -	Track +
6	Source	Track -	Track +	Search -	Source	Source	Source	Track -
7	Track +	Band / Disc +	Track -	Band	Track +	Track +	Track +	Audio
8	Track -	Preset / Disc -	Disc / FM +	Send / End	Track -	Track -	Track -	Power
9	Power	Select	Disc / AM -	Send	Band	Band	Band
10	Enter / Play	Attenuation	Answer	End	Answer **	Phone Menu	Reject / Source
11	Band / Program	Phone Receive	Voice		End** Answer Call	Answer / End Call
12	Receive	Phone Reject	On Hook		PTT **	End Call
13	End	Voice Dial	Off Hook			Voice
14	Voice	Power Mute
15			Preset +
* Advent, Boyo, Dual, Jensen, Rockford Fosgate & Visteon ** Jensen & Advent ONLY

Programming the SWC assignments

1. Turn the key to the ignition position.
2. Press and release programming button on the side of the interface.
3. Within 7 seconds, press the button that is to be learned on the steering wheel. The LED will turn off when the button is pressed. At this point you have two options:

A. For short press functionality: Release the button within 1.5 seconds. The LED will turn back on.
B. For long press functionality: Hold the button until the LED starts blinking. Release the button and the LED will go back to solid.

1. If you need to program more buttons, repeat step 3 for each additional audio function on the steering wheel.

2. If you come across a function in the chart that your steering wheel does not have, or you do not want to program, press and release the program button on the side of the interface to skip that function.

3. Once programming is completed, wait seven seconds. The LED will flash three times, indicating end of programming.

4. Test the interface for proper functionality. Whenever a SWC is pressed the LED on the interface should blink. If any function does not work, repeat the programming steps

Testing and Verification

1. Turn the ignition on. The LED on the interface will turn on and the +12v accessory wire will turn on.
2. Turn on the radio, and check balance and fade. Note: Premium Factory amplified Systems will not fade, as neither the aftermarket radio, nor the RP interface have the ability to control the amplifier's fader.
3. Verify that the factory subwoofer (if present) is playing.
4. Verify that all SWC are functioning properly.
5. Turn off vehicle and remove key. RAP will be active and keep the radio on for 10 minutes, or until the driver's door is opened.
6. The LED and radio will turn off when RAP turns off, or the driver's door is opened.

Rear Seat Entertainment (RSE); If equipped

1. Vehicles equipped with an overhead screen only: In this application, the GMRVD must be used in order to feed A/V into the factory screen from an aftermarket head unit (head unit must support A/V out). With the GMRVD, A/V will be passed from the aftermarket head unit to the rear screen, and audio can be heard through the headphones. The GMRVD will also pass the Auxiliary inputs on the rear of the center console, to the aftermarket head unit.
2. Vehicles equipped with an overhead screen AND headrest monitors: In this application, the headrest monitors will function independently from the overhead monitor. Neither video or audio, can be passed to or from the headrest monitors. The overhead monitor will function exactly as described in note 1.

Technical Support and Product Updates (Firmware)

The RP4-GM31 can be updated with new firmware as it becomes available using the PAC-UP interface updater (sold separately). Please visit www.PAC-audio.com/firmware for available updates.

Technical Support

[e-mail]

727-592-5991