I need some help please folks. 2002 Merc 50hp ELPTO tiller steer. I am having a total loss of power to the trim pump. Here is what I know. Battery is fully charged and the connections are tight. Brand new (aftermarket) trim pump installed. The issue is technically intermittent but I narrowed it down to when it occures.

Initial occurance happened as I was trimming up comming out of the ramp, motor stopped and would not move up or down. I could hear the solinoid engaging and clicking. Got it home, and removed the assembly. I found shaft seal in the pump went out and flooded the electical part of the pump with hydrualic fluid. So i replaced the pump motor.

Attached the new pump motor to the pump assembly. Plugged it into the the appropriate plugs and bench tested it. The motor is in the down position resting, the pump assembly is not attached to the motor and is laying on the deck. Cycled the ram all the way up and down several times with no issues. I then propped the motor up and bolted up the trim assembly. Plugged it back in, hit the button....nothing but a click.

Removed the trim assembly, layed it back on the deck, the motor is now propped up. Tested again, nothing. Put the motor back down, tested again, now the pump has power.

What I found was that the pump will only cycle when the motor is in the down position. If i manually lift the motor by hand while when holding the trim button down, it will run until the motor get to a certain point/ angle, the pump stops. If I lower it below that point it will engage again. I checked my wiring and connections looking for a short. Played with and pulled all the wires and could not get any change to happen.

Any input is appreciated. Im leaning towards it being one of the relays or the voltage regulator.

Sounds like it has a trim limit switch. Check the wires going to the pump from the relay for a limit switch.