Steering Wheel Control Harness (SWC) adaptors allow use of a vehicles factory steering wheel audio controls with an aftermarket source unit by converting the commands to a code that an aftermarket head unit can recognise.
Once you have your SWC harness selected to suit your specific vehicle, you then need to to select a patch lead based on the head unit brand and its connector. This steering wheel control harness suits Mazda CX-9 & Mazda3 models. Excludes those vehicles fitted with factory BOSE amplified systems.