Mercury Mariner 200, 225 Optimax Outboards Service Manual, 90-855348, Page 307Get this manual
Troubleshooting the "Down" and "Up" Circuits (All Circuits Inoperative) Check in-line fuse (under cowl) to see if fuse is blownBlown Fuse: .Correct problem caused fuse to blow.Replace fuse that
Fuse Not Blown: Connect Voltmeter red lead to Point and black lead to groundBattery voltage should be indicatedNo Voltage Indicated: .Check battery leads for poor connections or open circuits Check battery charge
Battery Voltage Indicated: .Connect Voltmeter red lead to Point and black lead to ground.Oepress "Up" trim button and check for battery voltage I
No Voltage Indicated: Connect red Voltmeter lead to Point 5, and black lead to groundI
No Voltage Indicated: Check that voltage is being supplied to control by performing the following checks :
Battery Voltage Indicated: .Check black ground wires for poor connection or poor ground, Point 10.Pump motor is faultyRefer to "Motor and Electrical TestsRepair", following