[2] The station formerly often simulcasted with KFNS (AM) (590 kHz), which is located in the St. Louis suburb of St Charles, Missouri.

[citation needed] On July 15, 2009, KFNS-FM began broadcasting an adult hits format, similar to local station WARH-FM (106.5).

On December 29, 2011, KFNS-FM changed formats once gain, this time to Hot Adult Contemporary, also as "Westplex 100.7".

May 7, 2017 St. Louis Market Report released, according to Inside Radio, with "The Morning Hangover" with DC, Eric, Zav & Ricki (joining from crosstown WARH-FM 106.5) rated #1 Men 18-49 & 25-54 and Persons 25–54 in St. Charles, Lincoln and Warren counties.

In 2022, audio of morning show host Vic Faust making insulting remarks to a co-host went viral.