If your are using blogger default search box just delete it and create your own money earning custom search engine by google.The main advantage of this search box is you can earn money by inserting your adsense publisher id.If you are have regular followers and visitors they search for old posts through search box.The adsense also pays much for search engines ads and impressions.So to day custom search engine follow the below tutorial.
Part1
1.Go to Google Cse( custom search engine).
2.Left side panel- New Search Engine
.
3.Choose any style and get code.
4.Left side panel –Make Money(click on it) and ad adsense id
Part2
1.Blogger->>Layout –>>Add a Gadget
2.Html/Java Script
3.Then add Cse Code
4.Save it.Bingo!