20 Amp fuse blows when tab switches are activated


Feb 28, 2012
West Michigan
Boat Info
1997 Sea Ray 240 Sundancer
Mercruiser 5.7L EFI alpha 1 Gen 2 drive
'97 Sea Ray 240 Sundancer. Yesterday, I was trimming the boat out and could not get the boat leveled. I shut the engine off and pressed one switch, then the other and could not hear the pump run. The 20 amp fuse was blown and I replaced it and pressed one of the buttons and the fuse blew.

Went back to the marina and unplugged the pump unit, replaced the fuse and pressed the switches on the dash and the fuse did not blow. The wiring at the switches looks fine - nothing is chafed. I could not see anything wrong with the wiring at the pump or connector either.

I plugged the pump back in and replaced the fuse and pressed the button - I heard the pump run for about two seconds and the fuse blew again.

I am thinking the issue is either a stuck ram or something in the pump is bad causing it to draw excessive current. I'm currently 400 miles from home and tools are limited. I may wait until I return home to troubleshoot this issue but it would be helpful to have some ideas on what to check or if there is something simple that I may be able to repair at the marina (not likely).

Tested the switches on the dash and they tested OK so I believe the issue is with the pump unit or the cylinders are frozen up but I'm leaning toward the pump unit since before the issue with the fuse, I was able to fully retract them, stalling the pump without blowing the fuse. I believe the units are able to be rebuilt. Hopefully Tom from Bennett can comment.

Once I am home and have access to the wiring diagram, I plan to unplug the pump and verify the correct voltages at the respective wire colors vs. the switch positions at the harness end. That will verify the wiring from the switches on the dash to the pump unit.

I'll continue to search for a method to test the pump unit but if anyone has any information, please post. Thanks.
I found the problem. The starboard solenoid is shorted. I unplugged the pump and verified the connections at the harness end with a test light per the chart in the owners manual while my son activated the switches. Everything tested good from the helm switches to the pump unit.

I then verified a good ground at the pump and used the fused jumper to individually apply power to each solenoid and the pump motor leads. When I put 12V to the green wire, the fuse in my jumper blew.

I plan to call the local marina tomorrow morning to see if they stock it or order it online. It is Bennett part no. VP1135-G in case anyone is interested.
I purchased a new starboard solenoid a couple of days ago and installed it. Trim tabs are now functioning again!

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