What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS DURING BOARDING, AFTER STARTING APU LOTS OF BROWN FLUID BLEW OUT OF THE AIR VENTS PRIMARILY IN THE AFT CABIN. ABOUT A GALLON OF BROWN FLUID ON AFT GALLEY FLOOR, PLUS SOME KIND OF STRANGE ODOR. FIRE DEPT. VERIFIED NON TOXIC. MAINTENANCE FOUND DRAIN AND VENT LINES CROSSED BEHIND THE G-5, REATTACHED IAW AMM 25-33-41. REMOVED, CLEANED, REINSTALLED ALL EFFECTED COMPONENTS.