Only one trim tab working?

Oceangeek

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Thank you for the help in advance. I have only one trim tab working. When I hit the lever for the non-working trim tab, I hear the trim motor working which means this is not an electrical issue ( I don't think). It sounds the exact same as when I hit the lever for the working trim tab but does not move.
Any suggestions on what this could be?
Thank you!
 

JJMag

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Definitely a Lotta good information on YouTube on tim tabs and it tells you exactly how to test each solenoid
but it sounds like it could be one of those solenoids on top of the electrical motor for the trim tab
 

Oceangeek

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Definitely a Lotta good information on YouTube on tim tabs and it tells you exactly how to test each solenoid
but it sounds like it could be one of those solenoids on top of the electrical motor for the trim tab
Yes from what I can tell after much research I'm thinking it is the green solenoid. I will be checking it tomorrow.
 
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Hookup1

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So the way this works is there are two valves (port and starboard) and a DC pump motor that runs in forward and reverse.

If you can raise and lower one tab that means that one solenoid is working and the motor can be run in both directions. It means you have a solid ground. That leaves one solenoid.

I would start at the switch and the crimp connector. See if you have power at the motor. You may be able to undo the connector clip the harness at the motor and verify. These units are very reliable - start at the switch.
 

blindmullet

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I just had to do this again and had a bad solenoid. This could be a good sticky for the forum. I have used it a handful of times. Rip tabman

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).
 
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Oceangeek

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I just had to do this again and had a bad solenoid. This could be a good sticky for the forum. I have used it a handful of times. Rip tabman

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).
Thank you for all the help. I greatly appreciate it!
 

Oceangeek

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So the way this works is there are two valves (port and starboard) and a DC pump motor that runs in forward and reverse.

If you can raise and lower one tab that means that one solenoid is working and the motor can be run in both directions. It means you have a solid ground. That leaves one solenoid.

I would start at the switch and the crimp connector. See if you have power at the motor. You may be able to undo the connector clip the harness at the motor and verify. These units are very reliable - start at the switch.
Thank you, I will be doing this tomorrow and I suspect it is just a bad solenoid. I will confirm tomorrow.
 

Hookup1

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Thank you, I will be doing this tomorrow and I suspect it is just a bad solenoid. I will confirm tomorrow.
Be sure to prove to yourself that its not the switch or the wire at the switch. I have seen solenoids go bad but most of the time its the switch/connector. Good luck!
 

Oceangeek

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Be sure to prove to yourself that its not the switch or the wire at the switch. I have seen solenoids go bad but most of the time its the switch/connector. Good luck!
It turns out to be a bad green solenoid after the tests. I am looking online and I see two bennett solenoids. One is 24V and one is 12V. There is no indication which one I have. Do you happen to know what voltage I should get? Its the original 96' solenoid.
 

Hookup1

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12 volt. Highly unlikely 24 volt - used mainly on the big rigs.
 

blindmullet

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It turns out to be a bad green solenoid after the tests. I am looking online and I see two bennett solenoids. One is 24V and one is 12V. There is no indication which one I have. Do you happen to know what voltage I should get? Its the original 96' solenoid.
They are around $60 on Amazon. Mine just showed up today.

Also, if they only have one of the colors just get it and cover with electrical tape or colored heat shrink. I have 2 greens on mine with red heat shrink on one.
 
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Oceangeek

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They are around $60 on Amazon. Mine just showed up today.

Also, if they only have one of the colors just get it and cover with electrical tape or colored heat shrink. I have 2 greens on mine with red heat shrink on one.
Good to know... I ordered the correct one. Installed it and everything is back to normal! Unbelievably easy to do.