Just picked up a '91 Sunsation Rocket 24x7 and the hatch and both tabs were not working when I first looked at the boat, but he replaced the swtiches on the helm and said everything was fine and used it for a bit.

Prior to picking it up, he told me the port side Bennett trim tab would not come back up, though it would pump down.... This is still the case.

The starboard side did work when I picked it up but has stopped working now??

And the hatch works in both directions...



This has me pretty confused... The pump makes running noise when any of the switches are activated. And obviously the pump is running in both directions since the hatch goes up & down.

I looked at Bennetts web site and they say if tabs go down but not up its either low voltage (boat fires up so probly not) or something with the wiring...

And with the starboard not working at all, they suggest checking wiring at helm and touching them together to isolate the issue.

But having multiple issues, in addition to the added hatch system Im lost other than just starting to replace trim solenoids.

Does this sounds like some kind of mixed up wiring and/or bad solenoids OR pump?

Appreciate any help I can get here!!

Pics of the setup, which look right compared to Bennetts diagrams...

I know the fluid is low, this was after I was messing with them and had to release pressure on starboard side to get tab to return.... All same symptoms when it was full

Contact Bennett. They have the best customer service period! Will tell you how to fix it and probably send you any parts you need for free.

yup!!!

cdaniel525,

Here is a link to a video that covers how the system works and troubleshooting http://www.bennetttrimtabs.com/videoplayer.php?vID=10

And this video covers "One Tab Operates, Other Does Not" http://www.bennetttrimtabs.com/videoplayer.php?vID=15

Below you will find troubleshooting you can print and take to the boat.
Look at step 3 and try it at the switch for the Trim Tabs and right at the pump. Check the connection at the pump for corrosion. Since the hatch lifter is working the problem is with the connections at the Trim Tab Switch or the pump. Also check and clean both ends of the black ground wire at the pump, even though the boat has good voltage corrosion on the ground wire could lower the voltage to it and could cause the valves not to open. The valves for the hatch lifter have a separate ground so they appear to be getting enough volts.

Let me know what you find and I will be delighted to help you get them operating again.

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).
__________________

+3 more should be like Bennett

Thanks a lot for those videos Tom! I already printed those same pages from PDF files off your site and plan on getting back to try some things out!
The videos really helped me out and gave me some ideas!!


Gotta agree with you guys... For a company to come on OSO and post up some repair procedure, thats definitely good stuff!

cdaniel525,

Sounds good! I will be standing by to hear what you find.

Tom
Bennett Marine

i love it. they say to call bennett. and you didn't even get a chance to call. they just came on here and started helping you troubleshoot it!!! THAT is cust service... i have a problem with my trim tabs. the pump is missing. maybe they will send me the parts I need for free!!! btw, the hatch and the tabs are 2 diff systems. nothing to do with each other.

I'm not sure I can help you with the missing pump
But actually the Trim Tabs and the Hatch Lifter share the same pump. Here is a basic diagram of the system:


Tom
Bennett Marine

Thats what happened to me a decade ago. I was shocked and will never forget it.