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Metra 40-GM21 Antenna Adapter

Works with select 1987-up General Motors vehicles — factory male to female Motorola antenna connector

Item # 12040GM21

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Item # 12040GM21

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C$10.99
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About the Metra 40-GM21 Antenna Adapter

Metra 40-GM21 adapter

The Metra 40-GM21 adapter lets you connect an aftermarket antenna cable to the factory radio. It has a female Motorola plug on one end and a right angled male GM antenna plug on the other. This adapter can also be used when installing a wired FM modulator with the factory radio. Please enter your vehicle information or call an Advisor at 1-888-955-6000 to find out if this adapter is compatible with your vehicle. Warranty: 60 days.

What's in the box:

  • 6.438" antenna adapter cable (one end terminating in a female Motorola plug and the other end terminating in a right angled male GM antenna plug).

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Metra 40-GM21 Antenna Adapter reviews

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Metra 40-GM21 Antenna Adapter

Crutchfield customer from Churchton, MD on 6/18/2019

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Good fit. Everything works as it says.

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0 of 0 found this helpful

Metra 40-GM21 Antenna Adapter

Crutchfield customer from Clarksdale, MS on 3/6/2019

2003 Chevrolet Silverado 1500

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Exactly what I needed to make the connection from module to my vehicle stock radio for installation of an external audio input.

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0 of 0 found this helpful

Metra 40-GM21 Antenna Adapter

Crutchfield customer from Havre De Grace, MD on 7/10/2018

1998 Pontiac Grand Prix

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Works great as all Crutchfield products do.

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0 of 0 found this helpful

Metra 40-GM21 Antenna Adapter

Jason from Walland, TN on 6/30/2018

1988 Dodge B Series

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The product was great just wrong application wouldn't work for my radio

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0 of 0 found this helpful

Plug and play

Doug from Knightdale, NC on 7/7/2017

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Plug and play it works

Pros: Easy install made rest of installation easier

Cons:

Crutchfield response on

0 of 0 found this helpful

Metra 40-GM21 Antenna Adapter

Jeremy L. from Swansboro, NC on 2/21/2017

2006 Hummer H3

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Exact fit. High quality and fast shipping. I have been buying from Crutchfield since I was a teenager and I will continue to buy from them.

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0 of 0 found this helpful

Metra 40-GM21 Antenna Adapter

Richard from Tavernier, FL on 9/25/2016

2003 Chevrolet Blazer

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Did not fit..... I ORDERED THE WRONG PART. They refunded the part immediately, no questions asked

Pros: Great customer support and prompt service

Cons: None

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0 of 0 found this helpful

Metra 40-GM21 Antenna Adapter

jg from North Carolina on 9/7/2015

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cheaply made had to electrical tape together

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Cons:

Crutchfield response on

1 of 1 found this helpful

Backwards

Crutchfield customer from Indiana on 1/20/2015

1998 Saturn SC1

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Did not fit. The connections were backwards.

Pros:

Cons: Did not fit, connections were the opposite of what my GM car required.

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1 of 1 found this helpful

perfect fit

jroman from rockford,il on 9/7/2014

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perfect fit adds satelite to factory radio using xm module

Pros: keeps factory radio adds satelite with module

Cons: none

Crutchfield response on

2 of 2 found this helpful

worked like a charm

joe from fredericksburg on 2/22/2014

2000 GMC Yukon XL

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my only gripe with gm vehicles is their ant. cables.does anybody know the reason for using small cables?

Pros:

Cons:

Crutchfield response on

1 of 1 found this helpful

Simple and easy

AlcoholicProgram from Pittsburgh, PA on 9/1/2013

1997 Cadillac DeVille

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Possibly the easiest thing to install so far. The GM Antenna adapter by Metra could not be any better. It does exactly as intended. If the low price scared you, or might even have you jump right into purchasing it, think again. The GM Adapter by Metra is the best product for its use and makes installing a new system that much easier and better.

Pros: Works perfect, simple install, very inexpensive.

Cons: Absolutely none.

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1 of 2 found this helpful

Metra 40-GM21 Antenna Adapter

Timi from San Mateo, CA on 8/17/2013

1998 Oldsmobile Cutlass

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Good product but couldn't use it because I did not specify which one I needed.

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0 of 0 found this helpful

Just the ticket too

Hap from MT on 7/4/2013

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This fits the radio and lets a regular antenna work on GM products.

Pros:

Cons:

Crutchfield response on

1 of 1 found this helpful

Too long

Ken from Saint Paul, MN on 5/19/2013

2001 Chevrolet Tahoe

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Worked like a charm

Pros: Plugged in tight.

Cons: Too long. Had issues with stuffing it an all the other wires back. behind stereo.

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0 of 0 found this helpful

Great Adapter

C P from Tuscaloosa, Al on 5/6/2013

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Great adapter, had no problems installing in my 2002 Chevy S-10.

Pros: Great adapter, easy installation

Cons: None

Crutchfield response on

1 of 2 found this helpful

Metra 40-GM21 Antenna Adapter

John W. from Cuba, NY on 3/26/2013

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Easily attached to my FM modulator.

Pros:

Cons:

Crutchfield response on

0 of 0 found this helpful

Worked great

TSub from Central KY on 1/29/2013

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This worked great for taking my Suburban back to a stock radio. The adapter made it easy to put a factory style radio back in since the antennas are somehow different. Had no issues with loose connections either.

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Cons:

Crutchfield response on

1 of 1 found this helpful

Don't Know Yet

Billy M from Sumrall, Mississippi on 1/2/2013

2006 Pontiac Grand Prix

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Had to use this with an adaptor for FM modulator of iPod. Did not fit very tight on a GM radio. Still works, but it seems like if ever hit a large bump in the road it's probably going to come out. But I may be wrong.

Pros: Works, so far.

Cons: Fits loosely in GM radio.

Crutchfield response on

0 of 0 found this helpful

Metra 40-GM21 Antenna Adapter

Michael from Flagstaff AZ on 2/21/2009

2004 Chevrolet Malibu (Classic)

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Why does GM use a weird miniturized Motorola antenna connector? Dunno, but they do. This is the answer (or if you are installing an XM modulator in-line, it is half the answer.)

Pros:

Cons:

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7 of 9 found this helpful

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Pros:

Cons:

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More details on the Metra 40-GM21 Antenna Adapter

Product Research

Features

Compatibility: 1987 and later GM factory radio with mini connector to universal antenna adapter cable (factory radio to universal antenna)

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Customer Q&A

Q
Crutchfield asked: Why did you buy this?
A
I bought an isimple radio module to tap into my FM radio so that I could install an accessory audio input. It has Motorola male & female connections. I bought an oem female to Motorola male adapter for the connection between the antenna and module and a Motorola female to oem male adapter for the connection between the module and the oem radio. [ Charles  Feb 21, 2019 ]
A
Because your website recommended it and said I needed it to use the FM modulation Blue tooth adapter. [ Cory  Feb 09, 2019 ]
A
To install the FM Direct Adapter to my 1998 Pontiac GP GTP with factory AM- FM CD Radio [ George  Jun 14, 2018 ]
A
I needed it for my truck [ Jason  Jun 05, 2018 ]
A
Received an e-mail from Crutchfield letting me know I would need this with my previous order. [ Brian  Mar 25, 2018 ]
A
Need it [ Rebecca  Mar 04, 2018 ]
A
suggested with another part [ Amanda  Feb 23, 2018 ]
A
need it [ DAVID A  Dec 16, 2017 ]
A
always has had good service and quality material from crutchfield. Why shop anywhere else? [ Doyle W.  Jun 21, 2017 ]
A
Fits my truck [ phillip  Aug 14, 2016 ]
A
My goal is to add an AUX port to the factory installed stereo system. This item is one of two items needed to complete this goal in my 2005 Pontiac G6 GT. [ Paul  Jul 29, 2016 ]
A
I choose one but both showed up on the order. If I don't need both delete whichever one is not needed. Thanks John [ Tech Brown  Jun 12, 2016 ]
A
price [ ronald  Jan 12, 2016 ]
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