Bennett Trim Tab system blows 20 A fuse

[khe]

I'm not sure where to post this - Moderators, please move to the appropriate forum as required.

'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 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.

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.

 

[khe]

The more I think about this problem, I don't believe it is a stuck cylinder - when I retract both tabs by pressing both the bow down sides of the buttons for four seconds, the fuse never blew. I'd think that would be the same load on the pump motor as a stuck cylinder. More testing is in order but I am thinking the pump motor is drawing excessive current and causing the fuse to blow.

 

[salty3rd]

Same thing happened on my last boat, ended up replacing the trim tab pump and motor assembly and it fixed the issue.

 

[khe]

Same thing happened on my last boat, ended up replacing the trim tab pump and motor assembly and it fixed the issue.

I suspect that will be the case with mine also. When it failed, I was 400 miles away from home and had limited tools, etc. We just trimmed the boat the old fashioned way - with assigned seats...LOL.

I plan to troubleshoot it in detail today. I did some research last night when I got home and apparently, the Bennett V-351 pump can be repaired.

 

[khe]

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.

 

[khe]

I purchased a new starboard solenoid a couple of days ago and installed it. Trim tabs are now functioning again!