Window Washer Level Warning Switch
WARNING: This page is about a different car, the 2003 Lexus GS 430, 2003 Lexus GS 300, 2002 Lexus GS 430, and 2002 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
Check that no continuity exists between the terminals with the switch OFF (float up). See Fig 1. Check that continuity exists between the terminals with the switch ON (float down). If operation is not as specified, replace the switch or inspect the ground point.