Mercury 15 EFI FourStroke, Service Manual

Page: 281 / 406

Problem/Solution
No. Problem Solution
1. Battery low or discharged Check battery.
2. Wiring reversed in remote control, handle switch, or tilt leads Verify connections.
3. Open circuit in tilt wiring
Check for an open connection.
4. Wire harness corroded through Replace wire harness.
5. Internal motor problem (brushes, shorted armature) Check for open connection. Replace motor.
6. Tilt switch failure Replace switch.
7. Relay not operating
Verify relays are functioning correctly.
Check voltage at tilt bullet connectors.
8. Fuse open (blown) Replace fuse.
Power Tilt Relay Test
a - Positive terminals (red)
b - Ground terminals (black)
c - Up relay terminal (blue)
d - Down relay terminal (green)
The tilt motor relay system, used on permanent magnet tilt systems, connects each of the two wires from the tilt 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 may 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 tilt system does not operate in one direction:
1. Disconnect the heavy gauge pump wires from the tilt control relay.
2. Check for continuity between the heavy leads from the tilt relays to ground.
Meter Test Leads
Meter Scale Reading
Red Black
Blue relay terminal Ground Ω < 20 Ω (full continuity)
Green relay terminal Ground Ω < 20 Ω (full continuity)
3. Replace the power tilt relay if either test shows an open circuit.
4. Connect a voltmeter to the heavy blue lead and to ground. There should be 12 volts on the blue lead when the up switch is
pushed. There should also be 12 volts on the green lead when the down switch is pushed.
Meter Test Leads
Meter Scale Reading
Red Black
Blue relay terminal Ground DC voltage Battery voltage (~12 V)
Green relay terminal Ground DC voltage Battery voltage (~12 V)
5. Replace the power tilt relay if it does not switch either lead to positive.
6. Reconnect the heavy gauge pump wires to the tilt control relay.
a
b
c
d
63554
Power Tilt
Page 5B-12 © 2018 Mercury Marine 90-8M0125265 eng NOVEMBER 2017