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Metra

Metra 40-GM20 General Motors Reverse Antenna Adapter 1988-2008

Metra 40-GM20 General Motors Reverse Antenna Adapter 1988-2008

Regular price $14.99 USD
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Review the application and system requirements

Confirm the size, power, connections, and included or separately required parts described on this page.

The Metra 40-GM20 Antenna Adapter is designed for select General Motors vehicles. It provides the antenna connection needed when using an aftermarket antenna with the original factory radio.

At a Glance

  • Vehicle-specific antenna adapter for select General Motors vehicles
  • Supports using an aftermarket antenna with the original factory radio
  • Female Motorola connector to male GM mini antenna connector
  • Helps maintain the AM/FM antenna connection during radio, antenna, navigation, or FM-modulator integration
  • Designed to avoid cutting factory antenna wiring when matched to the correct vehicle and radio configuration

System / Fitment Notes

  • Reverse antenna adapter for retaining the factory radio while adapting an aftermarket antenna connection

Exact Vehicle Compatibility

Find your vehicle below, then match the model year and factory-equipment details in the same row. Factory radio, amplifier, navigation, trim, speaker location, and connector differences can change which installation parts are required. If anything differs, contact MCOR before ordering.

Make Model Years Factory Equipment / Qualifier
Buick Century 1988-1989 —
Buick Electra 1988-1989 —
Buick LaCrosse 2005-2009 aka Allure in Canada
Buick LeSabre 1988-1989 —
Buick LeSabre 1990 —
Buick LeSabre 1991-1994 —
Buick Park Avenue 1988-1990 —
Buick Park Avenue 1991-1994 —
Buick Rainier 2004-2007 —
Buick Reatta 1988-1989 —
Buick Reatta 1990-1991 —
Buick Regal 1988-1994 —
Buick Rendezvous 2002-2007 —
Buick Riviera 1986-1989 —
Buick Riviera 1990-1995 —
Buick Roadmaster 1991-1994 —
Buick Skyhawk 1988-1989 —
Buick Skylark 1987-1995 —
Buick Terraza 2005-2007 —
Cadillac Brougham 1987-1989 —
Cadillac Brougham 1990-1992 —
Cadillac Coupe DeVille 1988-1989 —
Cadillac Coupe DeVille 1990-1993 —
Cadillac DeVille 1988-1989 —
Cadillac DeVille 1990-1993 —
Cadillac DeVille 1994-1995 —
Cadillac DeVille Concours 1994-1995 —
Cadillac Eldorado 1988-1991 —
Cadillac Eldorado 1992-1993 column shift
Cadillac Eldorado 1992-1993 console shift
Cadillac Eldorado 1994-1995 —
Cadillac Escalade, Escalade ESV, Escalade EXT 2003-2006 —
Cadillac Fleetwood 1988-1989 —
Cadillac Fleetwood 1990-1992 less Brougham
Cadillac Fleetwood 1993-1995 —
Cadillac Fleetwood 1996 —
Cadillac Fleetwood Brougham 1990-1992 —
Cadillac Seville 1988-1991 —
Cadillac STS 2005-2011 —
Cadillac XLR 2004-2009 —
Chevrolet Astro Van 1985-1990 —
Chevrolet Avalanche 2002 —
Chevrolet Avalanche 2003-2006 —
Chevrolet Beretta 1988-1990 With a/c
Chevrolet Beretta 1988-1990 Without a/c
Chevrolet Blazer 1992-1994 full size
Chevrolet C/K Pickup 1988-1994 —
Chevrolet Camaro 1990-1992 —
Chevrolet Caprice 1991-1993 —
Chevrolet Cavalier 1988-1990 —
Chevrolet Celebrity 1990 —
Chevrolet Cobalt 2005-2006 With OnStar
Chevrolet Cobalt 2005-2006 Without OnStar
Chevrolet Colorado 2004-2012 —
Chevrolet Corsica 1988-1990 With a/c
Chevrolet Corsica 1988-1990 Without a/c
Chevrolet Corvette 1984-1989 —
Chevrolet Corvette 1997-1998 —
Chevrolet Corvette 1999-2004 —
Chevrolet Corvette 2005-2013 —
Chevrolet Equinox 2005-2006 —
Chevrolet Express 2001-2002 —
Chevrolet Express 2003-2007 —
Chevrolet Kodiak C4500-8500 2003-2009 —
Chevrolet Lumina APV 1990-1992 —
Chevrolet Malibu 2004-2007 —
Chevrolet Malibu Classic 2008 —
Chevrolet Malibu Maxx 2004-2007 —
Chevrolet S-10 Blazer 1988-1989 —
Chevrolet S-10 Blazer 1990-1994 —
Chevrolet S-10 Pickup 1989-1993 —
Chevrolet Silverado 2003-2006 —
Chevrolet Silverado Classic 2007 —
Chevrolet Suburban 1988-1991 —
Chevrolet Suburban 1992-1994 —
Chevrolet Tracker 1998-2004 —
Chevrolet Trailblazer 2002-2009 —
Chevrolet Uplander 2005-2008 —
GMC C/K Pickup 1988-1994 —
GMC Canyon 2004-2012 —
GMC Jimmy 1988-1991 full size
GMC S-15 Sonoma 1986-1992 —
GMC S-15 Sonoma 1993 —
GMC Safari 1985-1990 —
GMC Safari 1991-1995 —
GMC Suburban 1988-1991 —
GMC Suburban 1992-1994 —
GMC Topkick C4500-8500 2003-2009 —
GMC Yukon 1992-1994 —
GMC Yukon Denali, Yukon XL Denali 2003-2006 —
GMC Yukon, Yukon XL 2003-2006 —
Hummer H2 2003 —
Hummer H2 2004-2007 —
Hummer H3 2006-2010 —
Hyundai Santa Fe 2003-2006 With Monsoon amp
Isuzu Ascender 2003-2008 —
Isuzu Hombre 1998-2001 —
Isuzu I-280, I-350 2006 —
Isuzu I-290, I-370 2007-2008 —
Kia Sorento 2003-2006 EX
Kia Sorento 2003-2006 LX With Sport Package
Oldsmobile Achieva 1992 —
Oldsmobile Alero 2001-2004 —
Oldsmobile Bravada 1991-1994 —
Oldsmobile Cutlass Calais 1988-1989 —
Oldsmobile Cutlass Calais 1990-1991 —
Oldsmobile Cutlass Ciera 1988-1989 —
Oldsmobile Cutlass Ciera 1990-1994 —
Oldsmobile Cutlass Supreme 1988-1989 —
Oldsmobile Cutlass Supreme 1990-1991 —
Oldsmobile Cutlass Supreme 1992-1994 —
Oldsmobile Eighty-Eight 1988 —
Oldsmobile Eighty-Eight 1989-1991 —
Oldsmobile Eighty-Eight 1992-1993 —
Oldsmobile Intrigue 1998-2001 —
Oldsmobile Intrigue 2002 —
Oldsmobile Ninety-Eight 1988 —
Oldsmobile Ninety-Eight 1989-1993 —
Oldsmobile Regency 1997-1998 —
Oldsmobile Silhouette APV 1990-1992 —
Oldsmobile Toronado 1983-1987 —
Oldsmobile Toronado 1988-1993 —
Oldsmobile Touring Sedan 1988-1990 —
Pontiac 6000 1986-1987 —
Pontiac 6000 1988-1989 —
Pontiac 6000 1990-1991 —
Pontiac Aztec 2001-2005 —
Pontiac Bonneville 1992-1993 —
Pontiac Bonneville Safari Wagon 1987-1989 —
Pontiac Firebird, Firebird Trans Am 1988-1989 —
Pontiac Firebird, Firebird Trans Am 1990-1992 —
Pontiac G6 2005-2008 —
Pontiac G6 2009 5th Digit VIN G, H or M
Pontiac Grand Am 1988-1989 —
Pontiac Grand Am 1990-1991 —
Pontiac Grand Am 1992-1995 —
Pontiac Grand Prix 1988-1989 —
Pontiac Grand Prix 1990-1991 —
Pontiac Grand Prix 1992-1993 —
Pontiac Grand Prix 2004-2008 —
Pontiac Lemans 1988-1993 —
Pontiac Montana SV6 2005 —
Pontiac Montana SV6 2006-2007 Canada only
Pontiac Sunbird 1988 —
Pontiac Sunbird 1989-1994 —
Pontiac Torrent 2006 —
Pontiac TransSport APV 1990-1992 —
Pontiac Vibe 2003-2008 —
Saab 9-7x 2005-2009 —
Saturn Relay 2005-2007 —
Saturn S Series 1991-1994 —
Toyota Matrix 2003-2004 —
Toyota Matrix 2005-2008 —

Fitment note: Year and model alone are not always enough to confirm compatibility. Match every factory-equipment qualifier shown for your vehicle, and contact MCOR Automotive if the radio, amplifier, navigation, speaker, camera, trim, or connector details are uncertain.

Installation Notes

  • Confirm exact year, make, model, factory radio, antenna connector style, and radio being installed before installation
  • Test-fit the antenna adapter and review manufacturer instructions before final assembly
  • Additional dash kits, wiring harnesses, steering wheel control interfaces, or factory feature-retention parts may be required
  • Professional installation is recommended for best results

What’s in the Box

  • Antenna adapter cable

Technical Specifications

  • Brand: Metra
  • Model: 40-GM20
  • Product Type: Antenna adapter
  • Application: Vehicle antenna integration
  • Connector Type: Female Motorola connector to male GM mini antenna connector

Identifiers & Packaging

  • MPN: 40-GM20
  • UPC: 086429007042
  • Sold As: Each
  • Included Components: Antenna adapter cable

Why Buy From MCOR Automotive

  • Authorized retailer for the brands we sell
  • Specialists in vehicle audio integration, radio replacement parts, and installation accessories
  • 22+ years of professional automotive electronics experience
  • Expert support for compatibility verification and proper setup
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