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bennett trim tabs

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On my 93 16 bonefisher, I'm having problem with trim tabs and have troubleshooted and problem seems to be from HPU to switch. On Bennett's info, there is only a red, green. blue and yellow wire and a ground, but on my boat, I have two 8 prong toggle switches with red, green, blue, orange, grey and 2 shades of yellow wires. Any ideas of the wiring diagram. Currently the switches will retract the tabs (bow up), but on bow down, the solenoids click, but pump doesn't run. Any ideas.

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Mine did the same thing on the right side only, was a bad switch. Replaced the contura type switch and all was good. Oh yeah, memory is coming back, I reversed/exchanged the wires on the switches and the left quit working and the right one did, that's how I isolated it to the switch.

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If you can't troubleshoot yourself, give Bennett a call--their customer service is outstanding. They recently helped me thru my problem, and gladly replaced what needed replacing. My unit was from 93 also!

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I am pretty sure that Maverick used their own switches, that's why the color discrepancy.

If you look at the pump you should see our 4 colors. The blue wire is the one that runs the pump for Tabs down. Take a look and see if you can tell what the wires at the pump equal in the harness.

If you can see that then you should be able to use step 3 below to troubleshoot the problem. Also check step 6 given the age of the system. If you are working on the boat this weekend I can be reached at tabmanhelp@gmail.com

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


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:


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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:content: Thanks Tab Man. The problem was the blue wire at the wire connection. I just butt connected and the problem was fixed. You've got to love a company that shows an interest in and helps a 21 year old product. Thanks Bennett Marine.

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I have to aqree.....I had some issue with my tabs two years ago now and the folks there were Excellent. Its been a long time since I have found customer service at that level of HIGH QUALITY...

after all the phone help they gave me, I'm basically an installation and trouble shooting tech now.....LOL.....

Really great great service....double thumbs up


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