Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 262Get this manual
Troubleshooting the "Up" Circuit (When "Down" Circuit Is OK) Remote Control NOT Equipped with Trailer Button
Connect Voltmeter red lead to Point and black lead to ground Depress the "Up" trim button
Battery Voltage Indicated: Connect Voltmeter red lead to Point 3
No Voltage Indicated: Connect Voltmeter red lead to Point and black lead to ground DepressDown" trim buttonIf battery voltage is indicated, wire is open between Points and 8
Battery Voltage Indicated: Connect Voltmeter red lead to Point Depress "Up" trim button
No Voltage Indicated: There is an open circuit between Point and positive (+) battery terminal Check for loose or corroded connections Check wires for openBattery Voltage Indicated: Pump motor wiring is defective Pump motor is defectiveNo Voltage Indicated: Relay Switch is defective