About the PAC RP4-GM32 Wiring Interface

Keep your factory features
Keep your factory features
PAC's RP4-GM32 wiring interface enables you to install a new car stereo while retaining useful factory functions in your 2012-up GM truck or SUV. You can upgrade to the higher sound quality of an aftermarket receiver while maintaining your factory-installed amplifier, safety warning chimes, Retained Accessory Power (RAP), and factory rear seat controls. If you're installing a navigation receiver, this adapter also includes the Vehicle Speed Sensor (VSS), parking brake, and reverse connections you need.
Control your new radio
This interface retains your factory steering wheel audio controls with your new stereo. The interface is pre-programmed for the factory steering wheel control functions, or you can even reassign the functions of the buttons.
Installation note: This interface will not retain OnStar capability, or maintain the fader controls on vehicles with the factory premium Bose® audio system.
Product highlights:
- works with select GM vehicles with factory navigation
- works with amplified and non-amplified systems (including Bose audio systems)
- provides Vehicle Speed Sensor (VSS), parking brake, and reverse connections for installing a navigation receiver
- retains factory steering wheel audio controls
- retains factory rear seat controls
- warranty: 1 year
- Our 60-day money-back guarantee
- MFR # RP4-GM32
What's in the box:
PAC RP4-GM32 Wiring Interface owner's manual
- Radio replacement/SWC interface module (for GM LAN 29-bit databus)
- 44-Pin harness
- Steering wheel control harness (4-pin connector to 3.5mm/blue wire)
- Instructions
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More details on the PAC RP4-GM32 Wiring Interface

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Features
Radio Replacement Interface: The PAC RP4-GM32 interface allows an aftermarket head unit replacement of the factory navigation radio in select General Motors vehicles with 29-bit GM-LAN databus system. 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. The RP4-GM32 also provides data bus driven outputs such as retained accessory power (RAP), vehicle speed sensor (VSS), illumination, reverse trigger, and parking brake.
- Bose Amplifier: If there is a Bose Audio system present, connect the RCA inputs of RP4-GM32's harness 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 the RP4-GM32's harness and connect the aftermarket radios speaker outputs to the remaining wire. Premium Factory amplified Systems will not fade as neither the aftermarket radio or the RP4-GM32 interface have the ability to control the amplifier's fader.
- Retained Accessory Power (R.A.P.): The ignition power source of many GM vehicles keeps the radio on until one of the doors is opened. This feature is called the R.A.P.(retained accessory power). The RP4-GM32 will retain this feature.
- Warning Chimes: The PAC RP4-GM32 will retain your vehicle's factory warning chimes.
- Navigation Outputs: The PAC radio replacement interface provides a VSS (vehicle speed sense), Parking Brake, Mute, and a Reverse Gear output to make installing an aftermarket Navigation radio simpler and less time consuming.
- RSE/RSC: The PAC RP4-GM32 lets you retain the vehicle's factory rear seat controls (RSC) and rear seat entertainment (RSE). In order to retain rear seat entertainment (RSE), you will also need the PAC GMRVD2 RSE retention harness (sold separately).
- Steering Wheel Control (SWC): The PAC radio replacement interface also lets you keep your GM vehicle's OEM steering wheel controls (no additional adapter required).
Note: The RadioPro4 (RP4-GM32) does not retain OnStar.
Vehicle Compatibility: The RadioPro4 (RP4-GM32) is compatible with select 2012-up GM vehicles fitted with a factory navigation radio and featuring the GM-LAN 29-bit databus system and 44-pin connector harness. Compatible vehicles as of 3/26/2014 include:
Make | Model | Year |
Chevrolet | Avalanche | 2012-2013 |
Silverado | 2012-2013 | |
Suburban | 2012-2014 | |
Tahoe | 2012-2014 | |
GMC | ||
Sierra | 2012-2013 | |
Yukon | 2012-2014 |
Note: As always, please consult Crutchfield's Outfit My Car to see if your vehicle is compatible. Click here for the most up-to-date list of compatible vehicles.
Radio Select Switch & Programmable SWC: 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. 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 to different buttons. The SWC functions can be easily programmed; see control settings and functions below. The interface retains programming even if your vehicle's battery is disconnected.
Switch Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | ||
Radio | Alpine | JVC | Kenwood | Clarion | Valor | OEM | Dual | Pioneer | Sony | Blaupunkt |
Control Functions | Volume +/- | Volume +/- | Volume +/- | Volume +/- | Volume +/- | Volume +/- | Volume +/- | Volume +/- | Volume +/- | Volume +/- |
Mute | Mute | Mute | Mute | Mute | Mute | Mute | Mute | Mute | Mute | |
Source | Source | Source | Source | Source | Source | Source | Source | Source | Source | |
Preset +/- | Track +/- | Play | Search +/- | Track +/- | Track +/- | Preset +/- | Preset +/- | Preset +/- | Track +/- | |
Track +/- | Band/Disc + | Track +/- | Band | Cursor up/down | Play/OK | Track +/- | Track +/- | Track +/- | Disc +/- | |
Power | Preset/Disc - | Disc/FM + | Send | OK | Band | Band | Band | Band | OK | |
Play/Enter | Select | Disc/AM - | End | *** | Cursor Up/Down | *** | Phone Menu | *** | *** | |
Band/Program | Attenuation | Answer | *** | *** | Answer/Hang-up | *** | Answer Call | *** | *** | |
Receive (phone) | Phone Receive/Reject | Voice Dial | *** | *** | *** | *** | End Call | *** | *** | |
End | Voice Dial | On/Off Hook | *** | *** | *** | *** | Voice Activation | *** | *** | |
*** | Power | Mute | *** | *** | *** | *** | *** | *** | *** |
Note: The SWC harness contains a Blue/Yellow wire and a 3.5mm connector. You will only use one of the connectors, based on your type of aftermarket radio. The Blue/Yellow wire supports Kenwood, Newer JVC, OEM and Blaupunkt radios. The 3.5mm jack supports Alpine, Jensen, Older JVC, Clarion, Pioneer, Sony, Valor, and Dual radios. Not compatible with Soundstream head units.
Wiring Connection Chart: The included wiring harness features the following hardwire connections.
Wire Color | Function |
Red | +12 Volt Accessory |
Yellow | +12 Volt Constant |
Black | Ground |
Blue | Power Antenna |
Blue/White | Amp Turn On |
Orange/White | Illumination |
White | Left Front Speaker + |
White/Black | Left Front Speaker - |
Gray | Right Front Speaker + |
Gray/Black | Right Front Speaker - |
Green | Left Rear Speaker + |
Green/Black | Left Rear Speaker - |
Purple | Right Rear Speaker + |
Purple/Black | Right Rear Speaker - |
Red/White | Parking Brake Detection (-) |
Purple/White | VSS Output |
Green | Reverse Output (+) |
RadioPRO App: PAC offers a Windows compatible RadioPRO App software program to help you configure the interface.
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