Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 191Get this manual
Electrical System Troubleshooting GENERAL CHECKS Before troubleshooting the Power Trim electrical systemcheck the following:
Make certain all connections are tight and corrosion free
3Check that plug-in connectors are fully engaged4Make certain battery is full charged
Refer to the preced ing four wiring diagrams for connection points when troubleshooting the electrical system (Connection points are specified by number
1Check for disconnected wires
Troubleshooting the "Down" Circuit (When "Up" Circuit is OK)
Connect Voltmeter RE lead to Point 1
and BLACK lead to ground
Depress the "Down" trim buttonBattery Voltage Indicated:
Con nect Voltmeter RED lead to Point 9
No Voltage Indicated:
Connect Voltmeter REO lead to Poinl4 and BLACK lead to groundDepressOown" trim buttonIf battery voltage is indicated, wire is open between Points and 1