Didn't work. At the bottom of the phone on the right hand side is an icon that looks like a magnifying glass. When I touch it, a page opens up which has a blue "g" on the left hand side, a microphone icon on the right hand side and a search box in the middle. Below that is a list of all my prior searches. When I tap the menu icon on the bottom left hand corner of my phone, I get a "seach settings" tab which I can access and a "manage search history" tab which is not highlighted. Tapping on the "search settings" tab takes to another window which is divivided (vertically) into "web" and "phone".
Looking for more advice.
Try going to www.google.com on your phone, and click on the search box. When the list of previous searches comes up, at the very bottom should be an option for "Clear Search History".