On Sept. 18, CBS will air the last episode of Guiding Light. The show began its life on the radio in 1937 and moved to television in 1952. But what was arguably the first soap opera, one that hovered near the top of the daytime ratings through the ’60s and ’70s, fell on hard times in the last decade. This year, Nielsen measured the show’s audience at 2.7 million viewers, down significantly from 5 million in 1999. While Wheeler, who took over Guiding Light in 2004, hoped to generate positive buzz with her new aesthetic, the results met with mixed reviews and rumbling from fans. But she had more on her mind than pleasing fans.