What was found
AFTER LANDING, #1 ENG AMBER FILTER BYPASS LIGHT ILLUMINATED. GROUNDED - YES. #1 ENG EEC BITE, FAULT 73-31071 FOUND DP0803 DISCONNECTED FROM S241 DIFF PRESS SW REF B737-800 WDM 73-31-11. W/NEW PRESSURE SW CONFIRMED THREADS ON OLD SWITCH & PLUG DP0803 NEED RPLCD THREADS CORRODED STRIPPED. REPLACED #1 ENG J8 HARNESS IAW B737-800 AMM 73-21-06. OPS CHKS GOOD GROUND VERIFICATION SUCCESSFUL. #1 ENGINE FUEL FILTER DIFFERENTIAL PRESSURE SWITCH REMOVED AND REPLACED REF AMM 73-34-01/401. OPS CHECK GOOD AND NO LEAK NOTED. #1 ENGINE FUEL FILLTER REMOVED AND REPLACED. REF AMM 73-11-02/401. OPS CHECK GOOD AND NO LEAK NOTED.