1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 237Get this manual
Troubleshooting the "Down," "Up" and "Trailer" Circuits (All Circuits Inoperative) Remote Control Equipped with Trailer Button continued from preceding page
Battery Voltage Indicated: Check BLACK ground wires at solenoids for poor connection or poor groundD Check BLACK motor lead for poor ground at Point 12If wire is grounded, the pump motor is faultyRefer to "Motor and Electrical TestsRepair," following
No Voltage Indicated: Connect RED Voltmeter lead to Point 11, and BLACK lead to ground
No Voltage Indicated: Check that voltage is being supplied to control by performing the following checks: DO NOT start engineD Turn ignition switch to "Run" positionD Check for voltage at any instrument, using Voltmeter