What was found
AIR TURN BACK DUE TO BOTH FWD LAVS AND ONE AFT LAV NOT FLUSHING IN AIR (FWD SYS). LAV FLUSH CONTROL RELAYS K2311 AND K2310 SWAPPED FOR TROUBLESHOOTING PURPOSES (WDM 38-32-11-1.1)AIRCRAFT PUT IN AIR MODE AND ALL LAVS FLUSHED CORRECTLY. REMOVED AND REPLACED RELAYS K2310 AND K2311 PER WDM 38-32-11-1.1, TOILET SERVICED BY VENDOR AND PERFORMED OPERATIONAL TEST OF ALL TOILETS PER AMM 38-32-00-725-142, FOUND SATISFACTORY ON GROUND. AIRCRAFT OK FOR SERVICE.T