This station received its original construction permit from the Federal Communications Commission on October 9, 1979.
[6][7] After the station was purchased by BMP Radio, the KJAV transitioned to a rhythmic oldies format, rebranding as "Jammin 104.9 The Valley's Old School".
The station had a morning show on weekdays with Tony Fornia and then played music with no disc jockeys afterward.
song "It's the End of the World as We Know It (And I Feel Fine)" just before starting every commercial break.
In 2009, Jack FM began broadcasting the games of the NBA Development League's Rio Grande Valley Vipers.