https://carmanuals2.com/lexus/is250c-2010-owner-s-manual-88949
Reference that for an owners manual, if you don't have one handy.
There is a fuse box in the trunk area with multiple convertible top fuses - 8 to be exact.
Your concern may not be due to blown fuses, but I suppose it's the first place to start checking.
RepairPal Certified shops can diagnose and repair your 2010 Lexus IS250. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.