Review on Axxess GMOS 01 Onstar Harness Adapter by Shahed Cleveland

This suspension is just what I needed for my 2003 GMC Sierra. I installed a new JVC head unit and needed a way to support all the alert sounds as well as the OnStar features. I chose this product because it is made by Metra, one of the big manufacturers in the aftermarket stereo market and I think it offers the best value for money. Metra technical support was also very helpful in clarifying a rather vague part of the instructions otherwise very easy to follow. I was able to follow the color coded schematic and make the necessary connections to complete the full installation. This harness is required to service the warning bells; (RE: door open, ignition plugged in, light on, etc.) because the noise comes from the driver's door speaker. It also supports a delayed switch-off option, where the key turns off before the door is opened, as well as the OnStar feature. This harness also allows you to add other available Metra modules such as steering wheel controls, navigation and Bluetooth for other GM vehicle functions. Just be aware of what radio system your car has as there are about four different systems that require different seat belts or if in doubt just call Metra and they will help you choose.