As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A WALK AROUND INSPECTION AND SUBSEQUENT OPERATIONAL CHECK, IT WAS DETERMINED THAT THE LEFT WING SURFACE DEICER WAS INOPERATIVE. A CLOSER INSPECTION REVEALED WEATHER CHECKING AROUND PREVIOUS BOOT PATCHES AND POSSIBLE WATER CONTAMINATION. REMOVED AND REPLACED BOOT IAW MM. DEICER APPEARED TO HAVE BEEN ON THE AIRCRAFT FOR SOME TIME.