Intermittent windshield washer fluid squirts AND wipers go on and off on its own automatically without me turning them on. It is very annoying. Has anyone else had this problem with their LS400? Any insight in this problem would be helpful. Thank you!

 

Is the button on your wiper stalk stuck inward, or does it not bounce back outward after being depressed and released?

On my car, this was broken so I rebuild it with a junk stalk. There is a spring on the inside of the button that allows two metal pieces to make contact when the button is pressed, causing the washer fluid and wipers to activate

If the spring is worn or the button is jammed and the contacts are touching intermittently, it could be causing your issue