Check the 15A "RAD" or "RADIO" fuse in the engine bay fuse box, and the 7.5A "ACC" or "CIG" fuse in the under-dash fuse box.
Note: Always use a digital multimeter to test and verify constant 12V, switched 12V, and ground before making permanent wire splices. Secondary Connectors (Steering Wheel Controls & Aux) Toyota 08600 Radio Wiring Diagram
A wiring diagram for an 08600-00823 will be completely different from one for an 08600-00980 . Getting your full part number is the only way to ensure you have the correct information. Check the 15A "RAD" or "RADIO" fuse in