Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 320Get this manual
POWER TRIM
Troubleshooting the "Up" Circuit
Connect Voltmeter red lead to Point and black lead to groundDepress the "Up" trim button
No Voltage Indicated: Battery Voltage Indicated: Connect Voltmeter red lead to Point 9Connect Voltmeter red lead to Point and black lead to groundDepress "Up" trim buttonIf battery voltage is indicated, wire is open between Points and 8
Battery Voltage Indicated: Connect Voltmeter red lead to Point 6Depress "Up" trim button
No Voltage Indicated: There is an open circuit between Point and positive (+) battery terminalCheck for loose or corroded connectionsCheck wires for open