Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 285Get this manual
Troubleshooting the "Down", "Up" and "Trailer" Circuits (A" Circuits Inoperative) Connect Voltmeter red lead POint and black lead 10 Point 30 Battery voltage should be indicatedNo Voltage IndicatedBatlery Vol tage Indicated:
Check batte ry leads for poor connections open ci rc uilsCh ec battery cha rgeTest fuse on trim pump (i' equipped)ReIer toMotor and Electrical Tests", see Table 01
Connect Voltmeter red lead 10 Polnt9OepresSlrailer bullon and check lor ballery voltage
ContentsTesllhermal overload switChBattery Vol tage Indicated:
Pump motor Is faullyRefer to "Motor Repair", see Table 01 Contents
Reier to "Motor and Electrical Tests", see Table of Contents
No Voltage ndicated: Connect red Voltmeter lead 10 Point 1O, and black lead 10 ground
No Vo ltage nd icatedCheck that vol tage Is being supplied to cont rol by perfo ming the following ch ecks;
Batl ery Vo ltage Ind icated: Th ere Is an open ci rcuit in each wire (green-whiteblue- wh iteand pu rple- white) between trim utlons and trim pum p