have a 87 merc 305 , alfa one power trim just clicks does not go up or down ...
pulled the pump out and put it on a battery and it works fine .. put it back in its doing the same thing clicking
it is either not getting ground , or not getting power...clean all of the wire connections in the system
that should include the switch , and check the wiring for breaks...my electrical problem with my tilt system , was pinched and broken wires around the base of the shifter..(the switch was at the top in the handle).
A volt/ohm meter will be a help in finding continuity in wires.
Let us know what you find.
I had the same problem, and my 350 merc w/bravo 3 has a inline fuse from the battery, removing the fuse verifying it wasn't blown, and then cleaning fuse contacts solved the problem.
It sounds like it's your solenoid(s) that are clicking. You can find instructions in the service manual for manually testing them, but it seems you already have tested out the motor and pump. I recently had a similar problem on my Alpha 1 Gen 1 and I was able to resolve by simply spraying down the solenoids with contact cleaner and letting them dry out. Otherwise they are under $20 each to replace.
