Electrical System Troubleshooting - Mercury 25 EFI Service Manual

Problem/Solution
No.
1. Low fluid level.
2. Defective hydraulic pump.
Trim cylinder piston or memory piston O‑rings
3.
leaking or cut.
Manual release valve leaking (check condition of
4.
O‑rings) (valve not fully closed).
5. Debris in system.
6. Battery low.
7. Electric motor defective.
8. Broken motor/pump driveshaft.
9. Air pocket under pump.
10. Defective up relief valve.
11 Trim cylinder shock piston ball not seated.
12 Thermal relief valve not seated.
Tube Ref No.
Power Trim and Steering
114
Fluid
Dexron III Automatic
28

Electrical System Troubleshooting

General Checks
Before troubleshooting the power tilt electrical system, check the following:
• Disconnected wires
• Connections are tight and corrosion free
• Plug‑in connections are fully engaged
• Battery is fully charged
Condition/Problem
Trim motor does not run when trim button is depressed.
Trim system trims opposite of buttons.
Tiller handle mounted trim buttons do not activate trim system.
Problem/Solution
No.
1. Battery low or discharged.
2. Open circuit in trim wiring.
3. Wiring reversed in remote control, handle switch or trim leads. Verify connections.
4. Wire harness corroded through.
5. Internal motor problem (brushes, shorted armature).
6. Trim switch failure.
7. Relay not operating.
DMT 2004 Digital Multimeter
90-8M0105568 eng MARCH 2016
Problem
Description
Condition of Trim System
Problem
Add Power Trim and Steering Fluid or ATF (Type Dexron III).
Replace pump assembly.
Replace trim cylinder piston and memory piston O‑rings.
Ensure that valve is fully closed. Inspect O‑rings.
Inspect for debris. Refill system with clean fluid.
Check battery.
Refer to Electrical System Troubleshooting.
Inspect for damage.
Purge system. Refer to Purging the Power Trim System preceding.
Inspect components. Refer to Power Trim Pump Disassembly.
Inspect ball seat for nicks and debris.
Replace manual relief valve.
Where Used
Power trim system
Power trim system
Check battery.
Check for an open connection.
Replace wire harness.
Check for open connection. Replace motor.
Replace switch.
Verify relays are functioning correctly. Check voltage at
trim bullets.
91‑892647A01
© 2016 Mercury Marine
Power Trim
Solution
Part No.
92-858074K01
Obtain Locally
Problem No.
1, 2, 4, 5, 6, 7
3
2, 4, 5, 6
Solution
Page 5B-11