Mercury Optimax 115 Service Manual page 318

ELECTRICAL SYSTEM TROUBLESHOOTING
CONDITION OF TRIM SYSTEM
A. Trim motor does not run when trim button is depressed.
B. Trim system trims opposite of buttons.
C. Cowl mounted trim buttons do not activate trim system.
PROBLEM
1. Battery low or discharged.
2. Open circuit in trim wiring.
3. Wiring reversed in remote control.
4. Wire harness corroded through.
5. Internal motor problem (brushes, shorted armature).
6. Blown fuse(s).
7. Trim switch failure.
8. Verify relays are functioning correctly.
POWER TRIM RELAY TEST PROCEDURE
The trim motor relay system used on permanent magnet trim systems connect each of
the two wires from the trim motor to either ground or positive in order to allow the motor
to run in both directions.
If the motor will not run in the UP direction, it could be either the UP relay is not making
contact to 12 volts OR the DOWN relay is not making contact to ground. The opposite is
true if the system will not run DOWN. When the system is not energized, both relays
should connect the heavy motor leads to ground.
To test which relay is faulty if the trim system does not operate in one direction:
1. Disconnect the heavy gauge pump wires from the trim control relay.
2. Check for continuity between the heavy leads from the trim relays to ground.
Replace the relay that does not have continuity.
3. Connect a voltmeter to the heavy BLUE lead and to ground. You should have 12 volts
on the BLUE lead when the UP switch is pushed. You should should also have 12 volts
on the GREEN lead when the DOWN switch is pushed. Replace the relay that does
not switch the lead to positive.
90-855347R1 JANUARY 1999
Ohmmeter
Leads Between
GREEN and Ground
BLUE and Ground
Resistance
(Ohms)
0
0
POWER TRIM
PROBLEM
1, 2, 4, 5, 6, 7, 8
3
2, 4, 5, 6, 7
Scale Reading*
(x____________)
Full Continuity (Rx1)
Full Continuity (Rx1)
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