For sale is a used working PAC SWI-CP5 Steering Wheel Control Interface. This allows you to use your factory steering wheel buttons with your aftermarket radio. It is compatible with a lot of vehicles but the list is too long to post here. The website has the vehicles listed. It includes the wiring harness and the diagram is on the back of the unit. You can also download the "ControlPRO" app for Android or iOS to program the unit.