Mercury 25 EFI Service Manual page 379

Step
Step 2: Check for
battery voltage at
point 3.
Step 3: Check for
battery voltage at
point 7.
Step 4: Check for
battery voltage at
each point 5.
Step 5: Check for
battery voltage at
point 6.
Step 6: Check up
relay.
Troubleshooting the Down and Up Circuits (All Circuits Inoperative)
NOTE: Refer to the preceding wiring diagrams for test points when troubleshooting the electrical systems. Test points are
specified by number.
DMT 2004 Digital Multimeter
Step
Step 1: Check Visually inspect power trim motor
fuse.
fuse.
Step 2: Check
Connect voltmeter red lead to point
battery
3 and black lead to battery ground.
voltage.
Connect voltmeter red lead to point
Step 3: Up
8 and black lead to battery ground.
trim switch.
Depress up trim button.
90-8M0105568 eng MARCH 2016
Test Procedure
Connect voltmeter red lead to point 3
and black lead to battery ground.
Connect voltmeter red lead to point 7
and black lead to battery ground.
Depress the up trim button.
Connect voltmeter red lead to each
point 5 and black lead to battery
ground.
Connect voltmeter red lead to point 6
and black lead to battery ground.
Depress the up trim button.
Test down relay. Refer to Power Trim
Relay Test preceding.
Test Procedure
Battery voltage measured:
• Go to Step 5.
No battery voltage measured:
• There is an open circuit between Point 3 and positive (+)
battery terminal.
• Check for loose or corroded connections.
• Check wires for open.
Battery voltage measured:
• Wire is open between points 7 and 8.
No battery voltage measured:
• Go to Step 4.
Battery voltage measured:
• Trim switch is faulty. Verify by performing continuity test.
No battery voltage measured:
• Check for loose or corroded wire at each point 5.
• Open circuit in wire supplying current to point 5.
Battery voltage measured:
• Go to Step 6.
No battery voltage measured:
• Relay is defective.
Relay is good:
• Pump motor wiring is defective.
• Pump motor is defective.
Relay is faulty:
• Replace relay.
91‑892647A01
Fuse blown:
• Correct problem that caused fuse to blow, and
• Replace fuse.
Fuse not blown:
• Go to Step 2.
No battery voltage:
• Check battery leads for poor connections or open circuit.
• Check battery charge.
Battery voltage measured:
• Go to Step 3.
No battery voltage:
• Go to Step 4.
Battery voltage measured:
• Check black ground wires for connection or poor ground at point
10.
• Pump motor is faulty.
© 2016 Mercury Marine
Test Result
Test Result
Power Trim
Page 5B-17