Step 1 - Precaution

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

When distinguishing trouble and replace the defective part, take necessary preventive measures against an electric shock. See REPAIR INSTRUCTIONS .
Some portions of the wiring harness in the this vehicle have circuits to which a high voltage is applied. To prevent an electrical shock, be sure to observe the following:
1. Wear insulated gloves during inspection.
2. Remove a service plug and do not start any repair operation before 5 minutes have passed. Then, confirm that the voltage at the output terminals has dropped down to 12 V or less.
  
  Fig 1: Removing Service Plug
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Use insulated tools during inspection.
4. When disengaging the wiring connectors, hold the connector bodies to avoid pulling the wires. When engaging the wiring connectors, be sure to engage them securely.
Do not leave the tools or parts (bolts, nuts, etc.) inside the cabin.
Do not carry metallic objects such as mechanical pencils or scales.