The station's influence and popularity waned with the waxing of FM radio in the late 1970s—by the end of the 1970s, however, as rock music continued its shift from AM to FM, WTRU had shifted to a full-service adult contemporary format.
As FM radio gained ground in the late 1970s, the station's influence began to wane. Nevertheless, by the end of the decade, it had transformed its programming to align with the shift from AM to FM in rock music, adopting a full-service adult contemporary format.