The Rio Grande Valley Border Patrol sector sees an increase in rescue operations for immigrants. CBS4 News Rio Grande Valley, Harlingen, TX. KGBT TV is the CBS subsidiary for the Rio Grande Valley in Texas. KGBT's Action 4 News broadcasts daily from the Rio Grande Valley in Harlingen, Texas. KGBT TV, virtual channel 4 (UHF digital channel 31), is a CBS-owned television station licensed to Harlingen, Texas, USA, and serves the greater Rio Grande Valley area.