Washer Signal Circuit: Description
WARNING: This page is about a different car, the 2008 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.
The distance control ECU detects washer operation. The cruise control will be cancelled by the distance control ECU if the windshield wipers operate in the HI or LO mode. By detecting washer operation, the distance control ECU allows the cruise control to continue even when the windshield wipers operate in the HI or LO mode.