The light usually lights if pressure is low do to lack of oil or a bad sensor. Maybe it's coincidence that the horn stopped working around the same time, maybe not. As stated above, I also keep my oil level at the top mark of the sight glass. I pre fill the filter but this isn't your issue. I would place the bike on level ground, straight up and down and check the oil level, adjust as necessary. If still flickers look into sensor or wiring issues.
2009 Concours 14
One day at a Time!!