Bennet port side trim tab stuck halfway

[cruiser262]

Hi
i hope that you are dooing good

i have bennet trim tabs on my 2000 Monterey 262 cruiser.
I have a problem...port side trim tab is stuck half way and when i start going beyond 3000 rpm the boat start listing to starboard(port bow up). I tried to compensate with the one working on starboard side but it doesn't seem to help that much.I opened the engine compartment and i could hear the motor working when pushing either switch up and down.I then removed the helm and i realized that the green cable behind the right switch(starboard side moving the port trim tab)was disconnected.After having put the helm back where it was i tried to push the right switch again up and down but now i can hear the noise only if i push it on bow up position.
can you help me?
many thanks

 

[Tabman]

Re: Bennet port side trim tab stuck halfway

Can you tell me what type of boat you have and how old the Trim Tab system is?

If the starboard Trim Tab is not moving and you can hear the pump running than the solenoid valve is not opening. It is really easy to troubleshoot.

Here is a link to a video that covers how the system works and basic troubleshooting Bennett Trim Tabs Video Player
And here is a link to a video that covers One Tab Operates, Other Does Not Bennett Trim Tabs Video Player

Below you will find troubleshooting that you can print and take to the boat. Doing step 3 will allow you to isolate the problem. Pay particular attention to the red wire since it controls the solenoid valve for the port Trim Tab.

Once you have done step 3 let me know what you find and I will be delighted to help.

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).

 

[cruiser262]

Re: Bennet port side trim tab stuck halfway

Hi Tom

my boat is a Monterey 262 cruiser and the trim tab system is a Bennet V351.I removed the helm to check the wirings behind the switches.On the right side switch that moves port trim tab which is the one not moving there is a green cable missing.(i desumed that is missing because the left switch has all cables plugged included the green one).

 

[Tabman]

Re: Bennet port side trim tab stuck halfway

Hi Tom

my boat is a Monterey 262 cruiser and the trim tab system is a Bennet V351.I removed the helm to check the wirings behind the switches.On the right side switch that moves port trim tab which is the one not moving there is a green cable missing.(i desumed that is missing because the left switch has all cables plugged included the green one).

It sounds like it is wired incorrectly. Here is a photo of the wiring connections for the switch.

Try moving the green to the other side and let me know what you find.

 

[cruiser262]

Re: Bennet port side trim tab stuck halfway

Try moving the green to the other side and let me know what you find.

i did it.No changes...a friend of mine was in the bilge while i was operating the switches, he could still hear the motor ,fluid was flowing to the lines because a he was pressing a bit the hydraulic cables connected to the Hpu .... but the port trim tab didn't move.may be it's a solenoid valve thing....

 

[Tabman]

Re: Bennet port side trim tab stuck halfway

i did it.No changes...a friend of mine was in the bilge while i was operating the switches, he could still hear the motor ,fluid was flowing to the lines because a he was pressing a bit the hydraulic cables connected to the Hpu .... but the port trim tab didn't move.may be it's a solenoid valve thing....

Did you try step 3 right at the pump? If you did and it did not work, then try reversing the hydraulic lines and see if the problem changes sides.

Let me know what you find.

 

[cruiser262]

Re: Bennet port side trim tab stuck halfway

Hi again Tom

today i borrowed a new hpu unit from a friend of mine...trim tab still not moving...now the starboard side one as well seems to move slower or not at all...maybe a low voltage from the batteries?Anyway i am going to pull the boat out of the water...the technician told me that may be some marine growth keeps the tabs stuck

 

[Tabman]

Re: Bennet port side trim tab stuck halfway

It is likely not marine growth on the actuators (rams) that is keeping them from moving. It is most likely low voltage. It is very important to check and clean both ends of the black ground wire at the pump, as well as the other connections.

Low voltage could indeed keep one or both Trim Tabs from moving, even if you hear the pump running.

 

[Don S]

Re: Bennet port side trim tab stuck halfway

When you replaced the power unit, did the tab retract when you had the lines off?

Try this, disconnect the actuator from the trim tab (2 screws). Then see if you can lift the trim tab up with the actuator disconnected. That will eliminate the tab hinge being the problem.
Next. with the actuator still disconnected, inside the boat (get some rags to catch the oil) disconnect the line at the actuator. Does the piston of the ram go all the way up? If it doesn't then you have a problem with that actuator.

If both steps above are ok, then you have wiring problems.