Connecting factory SWC to aftermarket radio via ASWC-1 and TAAXB

Here's notes on how I wired up a Steering Wheel Control Interface unit between factory steering wheel controls and a Kenwood aftermarket radio unit on a Gen2 (2004-2009) Prius.

The Scoshe TAAXB allows you to plug into the extra connector behind the radio and INCLUDES THE RESISTOR PRE WIRED so the HVAC controls work normally without an error message on the MFD /touchscreen. It's worth the $9 to not have to butcher the factory wires and install the resistor.

The Axxess ASWC-1 supports most radios and auto configures itself (usually). Some radios plug right in, others (like the Kenwood DDX9904S I installed) required the use of the included adaptor harness and the Brown wire hooked up to Kenwood Light Blue/Yellow SWC input. Check the manual of your particular radio unit.

Don't forget the ASWC-1 requires IGN power and ground to work.

Test everything before installing the radio back into dash, you may need to manually reconfigure the SWC interface if buttons don't work as you want, i.e. up and down don't move between radio presets, they scan for next station etc.

Zoom in on the wiring harness photo for comments on wiring. You can cut or ignore the wires you don't need for the Prius.