What was found
TYS - A/C WAS LEAVING BNA ON CLIMBOUT, THE CREW GOT A EICAS MESSAGE OF AIR-GROUND FAIL. A/C RETURN TO BNA WHERE MAINTENANCE ADJUSTED THE PROX SWITCHES AND TARGETS AT THE LT FOWARD, RT FOWARD AND AFT PROX SWITCHES, OPS CHECK GOOD AND WAS RELEASED. NO PARTS INVOLVED, JUST ADJUSTING OF SWITCHES AND TARGETS.