Trim tabs not working

g0tagrip

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I have a 2007 Marlin. I am trying to trouble shoot my trim tabs. They were working fine it must be something simple as they were fine on the 7th, then nothing on Friday the 13th. We checked the 20 amp fuse which seemed to be good.
I checked the manual and found the wiring diagram but it shows the pump on the starboard side but the text reads it is on the port side in the back berth under a panel. Tomorrow I will search to find it unless one of you guys knows which side and what panel to open. Also if anyone has any other ideas on what to do I would appreciate the advice?
Thanks for your inputs.
 

Tabman

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Below you will find basic troubleshooting. Do step 3 and let me know what you find.

Also here is a link to our video library, there is a troubleshooting section https://bennetttrimtabs.com/tech-help/video-library/

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).
 

g0tagrip

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So it turns out that the fork lift pushed my starboard trim tab well off center when they were picking the boat up from the water. The fork lift driver must have tried to move the boom arms with weight on the to adjust the position and that caused the system to not work, I got that fixed and the tabs are working fine now but .....I think I want to change my trim tabs out to ones that are flat and do not have the curved down edges so that the fork lift boom arms can't catch them by accident.
Tabman, does Bennett make a flat tab that would fit on my Marlin?
 

Fishtales

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Sounds like you need a new lift operator versus a new tab.
 

Tabman

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g0tagrip said:
So it turns out that the fork lift pushed my starboard trim tab well off center when they were picking the boat up from the water. The fork lift driver must have tried to move the boom arms with weight on the to adjust the position and that caused the system to not work, I got that fixed and the tabs are working fine now but .....I think I want to change my trim tabs out to ones that are flat and do not have the curved down edges so that the fork lift boom arms can't catch them by accident.
Tabman, does Bennett make a flat tab that would fit on my Marlin?

I'd have to see pictures of the transom, we make a bunch of custom Trim Tabs for Grady.

Tom
Bennett Marine