What was found
AFT LAVATORY WASTE LEVEL SHOWS FULL ON AFT FLT ATTNS PANEL, MOST OF AFT LAVATORYIES DO NOT FLUSH. SWAPPED LCM, NO HELP. LCM ALL LIGHTS FLASHING, (TEST MODE) CAUSING TANK TO INDICATING FULL AND PREVENTING LAVATORY FLUSH OPERATION. FOUND 'TEST FULL TANK SIMULATION' WIRE GOING TO AFT WASTE TANK LCM SHORTED TO OUTFLOW VALVE CAGE NEXT TO WASTE TANKS. REPAIRED WIRE, PROVIDED CLEARANCE, OPS RETURNED TO NORMAL. ALL LAVS FLUSH NORMAL.