VW up! / Seat Mii / Škoda Citigo Quadlock to ISO Adapter – CANbus Ignition (No SWC)

This ISO adapter harness is designed for VW Group vehicles fitted with the newer style Quadlock radio connectors, identifiable by the large power and ground terminals located at the rear of the factory radio. It adapts the original vehicle Quadlock connector to a standard aftermarket ISO connection, allowing the installation of a replacement car stereo while maintaining correct power and speaker connections. This adapter is suitable for VW up! (2016–2023), Seat Mii (2017–2021) and Škoda Citigo (2017–2021) models that use CANbus-controlled ignition.

The harness features a built-in CANbus interface that generates a key-present ignition power supply. This means the head unit powers on when the key is turned to the first ignition position and remains powered when the key is turned off, only shutting down once the key is fully removed from the ignition barrel. This behaviour ensures correct operation in vehicles without a traditional switched ignition feed.

PLEASE NOTE: This adapter is only suitable for vehicles with CANbus ignition and is not compatible with vehicles fitted with factory steering wheel audio controls, which require a dedicated steering wheel control interface.

Compatible with following Vehicles

• VW up! (2016–2023) Without Steering Wheel Audio Controls
• Seat Mii (2017–2021) Without Steering Wheel Audio Controls
• Škoda Citigo (2017–2021) Without Steering Wheel Audio Controls

20-186-IGN Compatible Factory Systems

How do i know if my VW UP! Seat Mii or Skoda Citigo has SWC?

SWC stands for Steering Wheel Control, the buttons on your steering wheel that let you operate your car stereo without taking your hands off the wheel. Common functions include volume adjustment, track skip, mute, and source selection, providing both safety and convenience while driving. When upgrading to an aftermarket radio, the factory steering wheel controls often won’t work automatically and require a dedicated SWC adapter to interface with the new stereo. This ensures your original buttons continue to function correctly, maintaining the seamless operation you’re used to.

It’s important to note that not all adapter harnesses support SWC, especially in CANbus-equipped vehicles. Some radios or ISO adapters only provide ignition and speaker connections, so the steering wheel buttons won’t function without a compatible SWC interface. Understanding whether your vehicle requires an SWC adapter can prevent installation issues and ensure your new stereo integrates perfectly with your factory controls.