Mercury Mariner 200, 225 Optimax Outboards Service Manual, 90-855348, Page 306Get this manual
Troubleshooting the "Up" Circuit
Connect Voltmeter red lead to Point and black lead to ground Depress the "Up" trim buttonI
Battery Voltage Indicated: Connect Voltmeter red lead to Point 9No Voltage Indicated: Connect Voltmeter red lead to Point and black lead to groundDepress "Up" trim buttonIf battery voltage is indicated, wire is open between Points and 8Battery Voltage Indicated: .Connect Voltmeter red lead to Point 6Depress "Up" trim buttonNo Voltage Indicated:
There is an open circuit between Point and positive (+) battery terminal.Check for loose or corroded connections Check wires for open