Review on Axxess GMOS 01 Onstar Harness Adapter by Ryo Flora

I bought this adapter to install an aftermarket radio on my 2004 GMC Envoy. It was very easy to install and works as described. The "sound" it replaces with the factory sound sounds a bit awkward at first, but it's not that bad. Just in case you're not exactly sure what it does. In some vehicles (I'm not sure which, so you'll have to do your own research) factory-installed radios control various other functions, such as the horn. On my 2004 Envoy, even after I park the truck, the radio stays on until you open the door. This function and sounds will be lost if you remove the factory radio without using the GMOS-01 adapter. Just make sure it's working properly before you cap everything! I received a defective device for the first time and had to wait a few days before I received a new one. If your calls don't work (the device's default volume is quite loud) or if the radio stays on after you open the door, then the device is defective. Oh, and don't forget to also buy an antenna adapter if you're installing a newer GM! They use a mini antenna that you need to convert to the larger type used in aftermarket radios. Revain sells an adapter for about $10.