Bennet Trim Tabs

Egret189

Cadet
Joined
Apr 6, 2011
Messages
13
My trim tabs have been inoperable for 6-7 years due to the hydraulic pump crapping out. I'm pretty sure it's just the electric motor as the solenoids can be heard clicking whenever I flip the switches, but no noise for the motor. Tried sourcing a new electric motor by itself instead of purchasing the whole hydraulic pump but not having much luck. Any ideas where I could find just the motor, or is there some reason the motor cannot be simply swapped out? Would rather not have to spend $250 for a new unit if possible. The boat is a full time saltwater fishing boat so it's no surprise that the motor crapped out after 8 years of use.
Thanks for any input.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,417
8 years is nothing. My tabs are going on 18 years of use
Have you done any trouble shooting? Mine stopped working a few years back and I traced it to a corroded wire connection. Cleaned up the connections and put them back service.
 

Tabman

iboats.com Partner
Joined
Feb 21, 2002
Messages
566
My trim tabs have been inoperable for 6-7 years due to the hydraulic pump crapping out. I'm pretty sure it's just the electric motor as the solenoids can be heard clicking whenever I flip the switches, but no noise for the motor. Tried sourcing a new electric motor by itself instead of purchasing the whole hydraulic pump but not having much luck. Any ideas where I could find just the motor, or is there some reason the motor cannot be simply swapped out? Would rather not have to spend $250 for a new unit if possible. The boat is a full time saltwater fishing boat so it's no surprise that the motor crapped out after 8 years of use.
Thanks for any input.

The pump body is epoxied and pinned to the electric motor and can not be removed and reinstalled in the field. Does the motor can look corroded? Do you have any idea how old the original system is?

Tale a look at the troubleshooting below and do step 3 and look at step 6 if it's an older system. Consider cutting the connector off the harness and doing step 3 right at the pump.

Let me know what you find,

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).
 

Egret189

Cadet
Joined
Apr 6, 2011
Messages
13
Tom,
Thanks for the great wealth of information. I have not gotten a chance to diagnose yet. I should get around to it tomorrow. As far as the unit goes, the motor can does have some considerable corrosion. The boat is a bit of a "salty dog". I'll try and get a picture up for reference tomorrow evening. Again, I am very grateful for all of the info guys! Will report back!
Jake
 
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