As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI OUT NUMBER ONE FUEL FILTER BYPASS LIGHT ILLUMINATED AND REMAIND ILLUMINATED APROXIMATELY 15 SECONDS, AND THEN EXTINGUISHED. POWER WAS AT IDEL. GROUNDED - YES. REF TSR711282 REMOVED AND REPLACED #1 FUEL DIFFERENTIAL PRESSURE SWITCH REF B737-800 AMM 73-34-01/801. OPSCHECK GOOD. NO LEAKS NOTED.