Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 189Get this manual
ELECTRICAL SYSTEM TROUBLESHOOTING CONDITION OF TRIM SYSTEM PROBLEM
ATrim motor does not run when trim button is depressedBTrim system trims opposite of buttonsCCowl mounted trim buttons do not activate trim system
PROBLEM
1Battery low or discharged2Open circuit in trim wiring345Wiring reversed in remote control Wire harness corroded throughInternal motor problem (brushes, shorted armature)