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I recently decided to upgrade my 2006 Silverado WT to have a backup camera, since my wife is temporarily driving it while her car is in the shop. Of course, this meant replacing the stock AM/FM radio. I went with Crutchfield and a Sony XAV-AX3700 as the specs for tuner sensitivity were exceptional, and I listen to both AM and FM stations. Install went fairly easy, aside from the fun of routing the camera cable from the rear of the truck to the grommet under the driver side floor.
My issue is that just sitting in the driveway, with the truck not even cranked, I get mostly a buzzing noise across the AM band, with the local news/talk station I listen to missing. On FM while most stations sound great, some that the factory tuner pulled right in are misssing.
The Crutchfield kit included a Metra antenna adapter that just adapted the small coax fitting on the GM antenna cable up to the more standard RCA side used by most radios.
I was using Copilot and another AI to discuss the problem, and they are both telling me that the issue is that GM powers an antenna amplifier in the base of the antenna mast by supplying 12V on the center wire of the antenna cable, and that aftermarket radios don’t do that. The AI suggests acquiring or making an adapter that will put the power from Sony’s blue/white antenna power wire output into the antenna wire.
Has anyone ever run into this? All the links copilot suggests for antenna power injector adapters to do this are dead links unfortunately. I can’t find much info on the net about this topic.
Anyone ever heard of this issue with the Silverado antenna and aftermarket radios?
I recently decided to upgrade my 2006 Silverado WT to have a backup camera, since my wife is temporarily driving it while her car is in the shop. Of course, this meant replacing the stock AM/FM radio. I went with Crutchfield and a Sony XAV-AX3700 as the specs for tuner sensitivity were exceptional, and I listen to both AM and FM stations. Install went fairly easy, aside from the fun of routing the camera cable from the rear of the truck to the grommet under the driver side floor.
My issue is that just sitting in the driveway, with the truck not even cranked, I get mostly a buzzing noise across the AM band, with the local news/talk station I listen to missing. On FM while most stations sound great, some that the factory tuner pulled right in are misssing.
The Crutchfield kit included a Metra antenna adapter that just adapted the small coax fitting on the GM antenna cable up to the more standard RCA side used by most radios.
I was using Copilot and another AI to discuss the problem, and they are both telling me that the issue is that GM powers an antenna amplifier in the base of the antenna mast by supplying 12V on the center wire of the antenna cable, and that aftermarket radios don’t do that. The AI suggests acquiring or making an adapter that will put the power from Sony’s blue/white antenna power wire output into the antenna wire.
Has anyone ever run into this? All the links copilot suggests for antenna power injector adapters to do this are dead links unfortunately. I can’t find much info on the net about this topic.
Anyone ever heard of this issue with the Silverado antenna and aftermarket radios?
Thanks!
I havean aftermarket that gets bad reception to. All aftermarket radios i ever had did the same. The buzzing noise seems like a bad or loose ground wire on the radio.
Well, I've ordered some parts that will let me inject 12V onto the antenna wire, and will report back here if it miraculously cures AM and FM reception. I may also pull the cover off the old factory radio and see if I can look at the PCB and determine if 12V is fed to the antenna output as well.
The way I am trying is a Metra 40-EU55 adapter that has been reported to work on a 2014 Silverado by at least one Amazon reviewer, which has the 12V lead. The trick though is that it uses a newer style FAKRA adapter for the antenna side, so I also ordered a FAKRA to Motorola style antenna connector adapter. I will put this between the back of the radio and the already installed adapter from the GM mini-barb to Motorola antenna size.
Note that there are a lot of inline antenna amps that go inline in the antenna cable, and have a 12V lead. NONE of those will work as the amplifier in the antenna base is still unpowered with those.
I'll report back in a couple of days with how this project goes.
I have now confirmed that the GMT800 at the very least, and likely newer and possibly older models, *DO* implement the AM loop antenna and some type of antenna amplifier in the base of the antenna, and which the FACTORY radio (and only the factory radio) supplies with 12V power via the center conductor of the antenna cable. No after market radio will supply that power, so when you install it, you end up with pretty much no AM and lower FM performance.
I cobbled together a cable that allowed me to send 12V power up the center conductor of the antenna wire, and believe it of not, suddenly I can now pick up my local AM talk stations. There is still a good bit of buzzing and interference across the AM band, but I blame that on being surrounded by modern electronics, as a portable radio I tested in the driveway has the same issue. I can't even USE an AM radio inside the house anymore with LED bulbs and computerized stuff causing interference.
So, let me clue you in to how I did this.
First - the antenna cable as you likely know on the GMT800 is a mini-barb type, and when I bought my new stereo from Crutchfield, they included a Metra 40-GM10 antenna adapter. But all that adapter does is convert from GM mini-barb to a more standard Motorola antenna connector used on most head units. You would THINK someone at Crutchfield or Metra would know about this antenna power issue, but apparently not.
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.
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 Saturday's install.
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.
Poor reception with aftermarket radio
