Port Trim Tab Won't Move

[djstewy]

Hello All,

Last season towards the end of the season my port trim tab stopped working and being a relative newbie to boat repair I held off on fixing it myself since it would be at the mechanics in a few weeks for winterizing and I'd have him look at it then. Well he told me it was low on fluid and it was good to go. Now I get the boat back from him this season and I splash it and sure enough the trim tab isn't working. I have a Bennett v351 and this time I filled up the fluid myself and while it was a little low it should have had enough ATF to do its work.

The starboard side tab works just fine with no problems but when I engage the port side tab the pump motor sounds like its having problems when I press the bow down button. Below is a video with audio of the pump in action, the third engagement you hear is my buddy pressing down the bow down button on the trim tab in question.

https://dl.dropboxusercontent.com/u/30069546/IMG_3830.MOV

Any help would be greatly appreciated! I'd hate to go another season barking at my buddies to shift their weight on the boat to level out. :lol:

Derek
94' Sea Ray 250 Express Cruiser

 

[Tabman]

Derek,

Low fluid will not affect just one Trim Tab. I watched the video and it appears that the valve for the port Trim Tab is not opening (that's why the pump sounds labored).


I will be delighted to help you get them working. Below you will find the troubleshooting for the system.

How old is the system?

Here is a link to a video that covers the basic system and general troubleshooting http://www.bennetttrimtabs.com/videoplayer.php?vID=10

Here is a link to a video that covers troubleshooting the pump if it runs and a Trim Tab does not move http://www.bennetttrimtabs.com/videoplayer.php?vID=22

Take a look at step 3 below, it will walk you through the test I think will isolate your problem. Do that test right behind the switch and right at the pump. Make sure that ALL the screws are tight on the back of the switch even if they don't have a wire attached, this could be your problem. Also pay particular attention to the red wire since it opens the valve for the port Trim Tab.

Let me know what you find and I will walk you through fixing it.

Tom McGow
Bennett Marine

Fluid: Automatic Transmission Fluid (ATF) any type. Hydraulic Power Unit is self bleeding, running the Trim Tabs up and down 3-4 times will purge air from the system.

Fuse: 12 volt system use 20 amp in-line fuse on positive. (24v & 32v use proportionately smaller)

Red= Port Valve
Green= Starboard Valve
Blue=Motor Forward (pump pressure)
Yellow= Motor Reverse (pump retract)
Black on HPU=Ground
Orange on Helm=Control Positive

Troubleshooting

1.If one side is not operating reverse hydraulic lines on the front of the Hydraulic Power Unit to determine if the malfunction is in HPU or actuator / hydraulic lines. If after reversing the lines symptom shifts to the other side the malfunction may exist in HPU. If the symptom remains on the same side, malfunction may exist with the actuator / hydraulic lines

2. Is the unit receiving a solid 12 volts? Low voltage will some times cause the solenoids to not open preventing the tabs from moving even though the pump motor is running.

3. Conduct the following test:
Remove the wires from the helm control and touch together as follows:
Operation=Reaction
Orange (+), blue, red= Port trim tab down
Orange (+), blue, green=Starboard trim tab down
Orange (+), blue, red, green= Both trim tabs down
Orange (+), yellow, red= Port trim tab up
Orange (+), yellow, green=Starboard trim tab up
Orange (+), yellow, red, green= Both trim tabs up

If the trim tabs function correctly for each wire grouping then the switch is at fault. Also note that any loose or missing screws on the back of the switch (whether a wire is connected there or not) can cause the pump to malfunction.

This test may also be done right at the pump by substituting a "hot lead" for orange. There is usually a connector to the wire harness within a foot or so of the pump. You want to check this connection for corrosion. You may wish to cut the connector off on the pump side and try the test on bare wires.

4. If you suspect corrosion on the wire connector near the pump, cut it out, test as above and reconnect using butt splices.

5. If you conclude the problem is in the pump, contact me. Bennett Trim Tab Systems carry a five year warranty.

6. Check to see if there is a relay in line on the wiring harness near the hydraulic power unit. If there is it is an Interrupter Relay (IR1000). It prevents the system fuse from blowing if you try to actuate one trim tab up and the other down at the same time. After you test as outlined above, try removing the relay from the wiring harness and retest the unit.(Note: the interrupter relay is no longer used in current Bennett Trim Tab systems and has been replaced with a Switches that "lock out" preventing a blown fuse).

 

[djstewy]

Hi Tom,

Thanks for the troubleshooting advice, I'll be heading down to my boat in the next couple of days to run through the diagnosis. As far as I can tell the system is original which would put it at 19 years old. One thing of note at the helm control is the switch for operating the port trim tab is EXTREMELY stiff and you really have to put some pressure on the switch to press it down. The starboard side takes a tenth the pressure to press the toggles down. Below is a picture of the Bennett switch I have at my helm, I was going to remove the helm control while I was down there to see if some WD40 would loosen it up some. Any chance the switch at the helm could be the issue? I figured since I was hearing the pump engage it couldn't be the helm switch.

Derek

https://www.dropbox.com/s/8ry8ai4qcn7wdyc/trim controls.jpg

 

[Tabman]

Derek,

Yes the switch could be the problem. The switch has to send positive 12 volts the the pump motor (we know that is working since you hear the pump) AND the valve at the same time. That means that it would need to energize the blue and red wire simultaneously to lower the port Trim Tab. If it failed in a way that it was only energizing the blue wire and not the red when you pushed it to lower port the Tab you would hear the pump run and it would sound strained as it pushed the fluid against the closed valve.

Doing step 3 right behind the switch will tell you if the switch as failed.

That is an old switch that we no longer make. If it needs to be replaced a current Bennett Rocker switch will wire in color for color. You may have to enlarge the hole for it about a 1/16".

Tom
Bennett Marine

 

[djstewy]

Tom,

I ran down to the dock today and worked my way through the troubleshooting. I took the switch out of the helm and manually applied both the blue and red wire to 12v power and while the pump turned on there was no action from the port valve. Using the green cable you could hear the action of the starboard valve opening in the pump. I then went back to the pump itself and separated the wiring harness and tested out each cable, with the same results as at the helm switch. I then swapped the green and red cable in the wiring harness to make sure the red cable was sound from the helm back to the pump, and it could operate the starboard valve fine.

At this point I'm thinking it has to be port solenoid valve, the red cable between the wiring harness and where it enters the pump looks great. Yet I still get no spark from touching the red cable to 12v or noise from the valve. If you agree where do you suggest picking up a replacement at? The pump itself is a v351.

Thanks again for all your help, I'd be clueless without your write up.

Derek

 

[Tabman]

I believe that the switch stuck at some point and kept current flowing to the port solenoid valve and "burnt it out".

I would recommend replacing the switch as well to prevent this from happening again.

For the valve the replacement part number is VP1135R Solenoid Valve - Red Wire, list price $57.00. I think West Marine carries them, also just about ant dealer can order them .

Here is a link to a video showing how to replace the valve http://www.bennetttrimtabs.com/videoplayer.php?vID=15

Tom
Bennett Marine

 

[djstewy]

Thanks Tom, I'll head down to West Marine and pick one up today. What part number do you recommend for the switch replacement?

Derek

 

[Tabman]

Derek,

The Rocker Switch is ES2000.

Tom