jfmorris
Member
I shared this information on another forum, but thought I would put it here, as this is something that I had to figure out on my own recently. To make a long story short - I recently decided to put a backup camera on my 2006 Silverado 1500 WT (work truck). Not that I need it, but its the truck my kids and family borrow, and with the long 8 foot bed, a toolbox that obstructs vision, AND a Tommy Gate lift gate adding almost another foot to the length, I always worry about someone backing into something with it. Once I got into it, I kinda was excited to replace the factory AM/FM radio, which has served as my sole sort of on-road entertainment all these years. I went with a Sony unit from Crutchfield, as I am picky about radio tuner performance, sensitivity, and such, and on paper, it was top notch. The kit from Crutchfield gave me a prewired harness, antenna adapter from the mini-barb GM uses to a more standard Motorola plug, and supposedly, everything I needed.
Once I spent several hours doing the install, which was mostly tied up in installing the backup camera under the lift gate and running the wire up front, you can imagine my surprise when I found nothing but static and noise across the AM band (yes, I actually listen to a couple of AM stations), and half the FM stations I listen to were missing! What the heck!
Well, a few weeks of research into the issue reveals something that Crutchfield and pretty much anyone else selling radios to GMT800 owners should know. Specifically, the factory radio sends 12V power up the center antenna conductor on that little mini-barb connector the factory antenna cable uses, to power an antenna amplifier in the base of the antenna out on the passenger fender! Without that 12V - no AM, and spotty FM performance!
No aftermarket radio provides that 12V power to the antenna unfortunately. Most as you probably know use a Motorola plug on the back of the unit.
So I went in search of a solution to this issue, but unfortunately, NO ONE currently sells an adapter that supplies power to the antenna that has the GM mini-barb socket on the antenna side, and a Motorola plug on the radio side. So... I had to improvise.
So to inject power, the ONLY suitable device I found was the Metra 40-EU55. This has a Motorola plug to go into the radio, and a separate blue power lead to connect to switched power (such as the blue & white wire coming from most receivers, or red switched accessory power), BUT the antenna side is a FAKRA connector, used on newer vehicles than the GMT800. So I had to find a FAKRA to Motorola plug adapter as well.
So we have, from antenna to receiver:
1. Metra 40-GM10 (mini-barb to Motorola plug) - Metra Part # 40-GM10 | Aftermarket Antenna | Metra Online (Mine came from Crutchfield)
2. Fakra Z Female to DIN Socket cable -
Amazon
(I used the one with the female Motorola plug and female Fakra).
3. Metra 40-EU55 (Fakra to Motorola plug + 12V power) -
Amazon
Here is a picture on the seat of the Silverado before I installed behind the radio. I added this between the radio and the Metra 40-GM10 that was already in there from the prior nstall.
I ended up connecting the blue wire on this to an unused red accessory wire in the pre-made wiring harness from Crutchfield, that was for a dangling connector to steering wheel mounted controls my truck doesn't have. Otherwise I would have cut the blue/white wire from the radio and spliced to it. Crutchfield had routed that to the connector for the factory harness, but it was an unused pin. I just skipped it as it was buried in the braid/wrap around the harness they made.
I hope this helps someone else who wonders why their AM radio stops working when they replace the factory unit in their GM truck or car! And I am kinda ticked I had to research this and work on it, and that Crutchfield, Metra and other folks that DEAL with car audio for a living don't know to give us a harness that supplies the 12Vdc to the antenna wire that the factory radio supplied.
To be honest, I could probably have built something with an inductor and capacitor, maybe a diode or two, but was too lazy to deal with that.
Hope this helps someone else who is having this issue. After this - all my AM and FM stations are back, and better than before.
Once I spent several hours doing the install, which was mostly tied up in installing the backup camera under the lift gate and running the wire up front, you can imagine my surprise when I found nothing but static and noise across the AM band (yes, I actually listen to a couple of AM stations), and half the FM stations I listen to were missing! What the heck!
Well, a few weeks of research into the issue reveals something that Crutchfield and pretty much anyone else selling radios to GMT800 owners should know. Specifically, the factory radio sends 12V power up the center antenna conductor on that little mini-barb connector the factory antenna cable uses, to power an antenna amplifier in the base of the antenna out on the passenger fender! Without that 12V - no AM, and spotty FM performance!
No aftermarket radio provides that 12V power to the antenna unfortunately. Most as you probably know use a Motorola plug on the back of the unit.
So I went in search of a solution to this issue, but unfortunately, NO ONE currently sells an adapter that supplies power to the antenna that has the GM mini-barb socket on the antenna side, and a Motorola plug on the radio side. So... I had to improvise.
So to inject power, the ONLY suitable device I found was the Metra 40-EU55. This has a Motorola plug to go into the radio, and a separate blue power lead to connect to switched power (such as the blue & white wire coming from most receivers, or red switched accessory power), BUT the antenna side is a FAKRA connector, used on newer vehicles than the GMT800. So I had to find a FAKRA to Motorola plug adapter as well.
So we have, from antenna to receiver:
1. Metra 40-GM10 (mini-barb to Motorola plug) - Metra Part # 40-GM10 | Aftermarket Antenna | Metra Online (Mine came from Crutchfield)
2. Fakra Z Female to DIN Socket cable -
Amazon(I used the one with the female Motorola plug and female Fakra).
3. Metra 40-EU55 (Fakra to Motorola plug + 12V power) -
AmazonHere is a picture on the seat of the Silverado before I installed behind the radio. I added this between the radio and the Metra 40-GM10 that was already in there from the prior nstall.
I ended up connecting the blue wire on this to an unused red accessory wire in the pre-made wiring harness from Crutchfield, that was for a dangling connector to steering wheel mounted controls my truck doesn't have. Otherwise I would have cut the blue/white wire from the radio and spliced to it. Crutchfield had routed that to the connector for the factory harness, but it was an unused pin. I just skipped it as it was buried in the braid/wrap around the harness they made.
I hope this helps someone else who wonders why their AM radio stops working when they replace the factory unit in their GM truck or car! And I am kinda ticked I had to research this and work on it, and that Crutchfield, Metra and other folks that DEAL with car audio for a living don't know to give us a harness that supplies the 12Vdc to the antenna wire that the factory radio supplied.
To be honest, I could probably have built something with an inductor and capacitor, maybe a diode or two, but was too lazy to deal with that.
Hope this helps someone else who is having this issue. After this - all my AM and FM stations are back, and better than before.
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