What was found
LEFT MAIN FUEL QTY INDICATOR WENT BLANK. INDICATOR CAME BACK ON/OFF FOR LEFT FUEL QTY BUT READ IN ERROR BOTH HIGH AND LOW. GROUNDED - YES. REMOVED AND REPLACED COMPENSATOR F15L AND PROBES F1, F2L, F3L, F4L, F5L, F6L REF B737-800 AMM 28-41-21/400. REMOVED AND REPLACED TANK UNITS F7L, F10L, F11L, F12L REF AMM 28-41-21/400. REPLACED TANK UNIT F8L AND F9L REF AMM 28-41-21/400. PERFORMED AMM 28-41-21-710-801, ALL TANK UNITS AND COMPENSATOR VALUES ARE WITHIN LIMITS. FQIS SYSTEM TEST PASS REF AMM 28-41-00-730-801. ETOPS GROUND VERIFICATION SUCCESSFUL. FOR WORK ACCOMPLISHED. FQIS SYSTEM TEST PASS REF AMM 28-41-00-730-801. WHILE TRANSFERING FUEL, INDICATOR READS CORRECTLY WITH NO ABNORMALITIES. CLEARS MEL 28-6B AND MEL 28-12B. A/C RETURNED TO NORMAL CONFIGURATION, BUSSING PLUG REMOVED AND STOWED, CONNECTOR D11312 RECONNECTED AND SAFTIED. ETOPS GROUND VERIFICATION SUCCESSFUL.