Review on Metra GMOS OnStar Interface Systems by Sergey Chodavarapu

Instructions could be better. This is not for beginners. This is a manufacturer specific (GM) harness, not an automobile or receiver harness, meaning that over 16 wires had to be connected to the receiver harness, soldered together and heated. - Shrinking by heat. This kit comes pre-wired with a 16-pin connector that plugs directly into a separate (optional) Axxess ASWC-1 controller (see my review there for specific bugs I've encountered with this product). Although I had some problems with ASWC-1, this interface worked without any additional configuration.