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PAC OS-1 Wiring Interface

Connect a new car stereo and retain OnStar® and the Bose® audio system for select GM vehicles

Item #: 127OS1BOSE

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8 Reviews | 3 questions - 4 answers

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PAC's OS-1 wiring interface lets you replace a General Motors radio (without RDS) with an aftermarket receiver while maintaining operation of the OnStar® system and the GM Bose® amplifier and speakers. The kit includes:

  • the OEM-1 premium sound system interface, which allows quick connection of an aftermarket receiver (or an additional amplifier) to the GM Bose system, without the need to cut wiring;
  • the OS-1 adapter, which allows the use of the OnStar system with an aftermarket receiver. The OS-1 has on-board switching and built-in amplification that allows audio from the OnStar system to play through the two front speakers (factory or replacement) when OnStar is active, while muting the replacement radio.

The OS-1 can also send OnStar audio to an external set of speakers if desired. There are separate right and left gain controls for OnStar audio, and an LED indicator that turns on when the OS-1 receives an "On" command from the OnStar® system. Dimensions: 4-13/16"W x 1-1/16"H x 2"D (OS-1 adapter). Please enter your vehicle information or call an Advisor at 1-888-955-6000 to find out if this model is compatible with your vehicle.

Important Note: The OS-1 kit will interface with GM Delco/Bose radios that do NOT have the "RDS" option. If there is an "RDS" logo on the radio face, the OS-1 kit will not work. Warranty: 1 year.

Note: Most vehicles will require additional installation parts — please identify your vehicle if you haven’t done so. You can also call an Advisor for more information.

PAC OS-1 Wiring Interface Reviews

Average Customer Review:

8 Reviews

Easy Install

Written by: Anonymous from Shinnston, Wv on April 7, 2015

1999 Cadillac Escalade
Crutchfield Customer Review (What's this?)

Installed very easily in my 1999 Escalade. Works great. The only snag i hit came when I had to bypass a certain wire. Called Crutchfield tech support and they had me sorted out in under 10 minutes. Great product and even better service.

Pros: Easy install


Denali installation

Written by: Leobardo from santa maria, ca on April 5, 2015

2001 GMC Yukon Denali
Crutchfield Customer Review (What's this?)

Hello, the installation went flawlessly, and everything worked the way it's supposed to. Steering wheel controls worked well only after programming each button.

Pros: Keeps functional all of your factory buttons.

Cons: Programming each button.

no questions needed

Written by: Denali from Bullhead City, Arizona. 86442 on February 2, 2015

2001 GMC Yukon Denali
Crutchfield Customer Review (What's this?)

No questions needed. Easy to use and had it all in and installed in less than an hour.

Pros: Good directions. Easy to read and understand.

Cons: No cons with this product

Neat piece of tech

Written by: Anonymous from Boston, MA on August 1, 2014

Crutchfield Customer Review (What's this?)

This piece of tech is pretty awesome and for someone who has been installing stereos for over 20+ years a a a hobby it sure made life a lot easier. Plus it made everything work which would have been just about impossible without it.

Pros: Pretty straight forward install. Just match the colored wires.

Cons: The solid blue wire can be tricky here. I had read many people say it had to be attached to the blue/white remote wire . But when this was done in my 02 Escalade it caused the remote wire to be a constant and the amp never turned off, which drained my battery overnight. Even Crutchfield tech said the blue wire should be hooked to the blue/white, but I don't think they knew it would do that. Other than that this modular is awesome.

Crutchfield response on August 5, 2014 Upon reading this review, our Tech Support team contacted the manufacturer to see if they had any additional information. We then followed up with the customer to get more details about his situation. Only the blue/white wire should be used in this vehicle. We have noted this issue in our database to help future customers.

PAC OS-1 Wiring Interface

Written by: josh f from Eau Claire, WI on May 7, 2013

Crutchfield Customer Review (What's this?)

Works great and the clutchfield support was dead on! I would recommend buying through them. Thanks clutchfield for making my install a breeze!

Pros: Works great

Cons: None

Perfect Integration

Written by: MattyP from Wichita, KS on December 26, 2012

2001 Chevrolet Suburban
Crutchfield Customer Review (What's this?)

Needed this adapter to hook up a JVC head unit to my Bose-equipped 2001 Suburban. The install went smooth as anything, the instructions are fairly clear but of course Crutchfield's tech guys are the best in the business to help so don't even sweat it. Since you will be connecting loose-end wires together to your head unit wiring harness, you'll need to purchase some wiring connections. I recommend the telephone-wire type connectors that you can get at the home improvement store (you put both wires into a little fastener and clamp down with pliers and boom...done). Everything hides behind the head unit somewhere in your dash and away you go. Easy breezy.

Pros: Seemless and easy

Cons: None

PAC OS-1 Wiring Interface

Written by: Derek from OKC, OK on May 24, 2009

2002 Pontiac Grand Prix
Crutchfield Customer Review (What's this?)

Good product, does what is advertised. The only downside is the relay in the harness. Mine failed within a couple of hours of operation and ended up removing it all together. Once the relay was removed everything went back to working perfectly.



Bose system adapter

Written by: BK's account from Montgomery, AL on February 8, 2008

Crutchfield Customer Review (What's this?)

This adapter was used to integrate a Kenwood DVD into a 2001 Yukon Denali. Supports the On-Star and seamlessly installs to use the stock bose amps and speakers. One note, the steering wheel remote functions will not work. You'll need a separate RF remote adapater for that.
Also found the the OEM-1 component is not required, in fact the system works better without it (less road noise).

With this adapter, it was easy to install an aftermarket stereo.

Recommend the Crutchfield website provide more detailed installation instructions.



Hands-on research

What's in the box?

Download owner's manual

  • OS-1 GM OnStar Interface adapter with attached 7" wire harness (6-pin Molex plug on end)
  • OEM-1 Factory Sound System Interface
  • 12" OS-1618 harness
  • One 8" OS-RAD harness with attached Emitter
  • One 7" AMP-GM21A harness
  • Installation Instructions

Product Research


Applications: The OS-1 BOSE is an interface that allows for the replacement of a GM factory radio, that doesn't have RDS, and maintain the operation of the OnStar navigational system and the factory GM Bose sound system. The OS-1 BOSE has on board switching and amplification that allows the audio from the OnStar system to play through the front speakers when OnStar is active, and mutes the replacement radio.

Compatibility: The OS-1 BOSE is compatible with the following select 2002 and older General Motors vehicles: Chevy Avalanche, Cadillac Escalade, Chevry Silverado, GMC Sierra, Chevy Surburban, Chevy Tahoe, and GMC Yukon, plus 2000 and older Chevy Blazer, GMC Jimmy and Chevy Lumina. It will also work in some 1999-2003 Pontiac Grand Prix and 98-99 Bonneville. The OS-1 BOSE will interface with all GM radios that use 21-pin/9-pin connectors and have Bose amplifier/speakers. If there is an "RDS" logo on the face of the radio, this interface will not work. Please check the Crutchfield Vehicle Selector for compatibility with your vehicle.

Contents: The OS-1 BOSE interface consists of the OS-1 On-Star interface and the OEM-1 Premium Sound Interface, plus the wire harnesses that plug between the two interfaces and the factory sound system and On-Star system.

Left and Right Gain Controls: The OS-1 adapter has independent left and right controls that adjust the level of audio coming from the OnStar system.

LED Indicator: This is an indicator on the OS-1 that lights up when OnStar is active.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Customer Q&A

3 questions already asked

If you purchased the product from Crutchfield, feel free to contact our Tech Support team. They can walk you through the settings on the product and see if there may be a fix. Our toll-free Tech Support number is printed on your invoice, and is also available under the "My Orders" tab in the "My Account" section of our website. If you did not purchase the unit from Crutchfield, then you may want to contact the manufacturer. You can also post your question in our forums: Or try our online support center: [ Krissy  Feb 17, 2015 ]  Staff
I have never used the on star , actually i want to remove this system. Will this stereo system work on my tahoe ? [ Diego  Nov 27, 2014 ]
You will want to contact an Advisor by phone (1-800-324-9695) or online chat to discuss compatibility with your factory system. They will be able to pull up your vehicle and see if this is needed. [ Jeff  Mar 18, 2014 ]  Staff
You will want to contact an Advisor by phone (1-800-324-9695) or online chat to discuss compatibility with your factory system. They will be able to pull up your vehicle and see if this will integrate. If it does not, then they will also be able to discuss other options with you. [ Jeff  Mar 13, 2014 ]  Staff

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