Skip Navigation

PAC AMP-GM21B Pontiac Factory Integration Adapter

Required with OS-1 Bose Interface for 1999-02 Pontiac Grand Prix to retain OnStar® and Bose® systems

Item #: 127GM21B

Be the first to write a review

This item is no longer available.

Original Price: $11.99

Shop all Factory System Adapters

Does it fit my car?

Select your car

Find what fits your car

Can't find your exact car?

Pacific Accessory Corporation's GM21B harness works in conjunction with the OS-1 BOSE adapter to allow you to replace a GM radio (without RDS) in a 1999-02 Pontiac Grand Prix. You can install an aftermarket receiver, and still maintain operation of the OnStar® system and the GM Bose® amplifier and speakers. Warranty: 1 year.

Important Note: The GM21B harness and OS-1 BOSE adapter will only interface with 1999-02 Pontiac Grand Prix radios that do NOT have the "RDS" option. If there is an "RDS" logo on the radio face, the harness and adapter kit will not work. In order to determine compatibility with your vehicle, please use the vehicle selector on our site, or call a Sales Advisor at 1-888-955-6000.

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 AMP-GM21B Pontiac Factory Integration Adapter Reviews


Hands-on research

What's in the box?

Download owner's manual

  • 7" Wire harness

Product Research

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.