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Bennett Trim Tab Not Moving

Old 02-08-2014, 07:10 AM
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Lightbulb Bennett Trim Tab Not Moving

Hi all,

Been trying to get my port trim tab working for a few weeks now and before I get covered in ATF fluid again thought i should check in with you fellas in case there's an easier way to do this...

I tried my best to do my homework before asking, and found the troubleshooting guide and followed it.

Starboard tab works fine. Port tab does not move. HPU clicks and pumps but no movement in the actuator, I can move it by hand so it's not frozen. It worked once or twice when I filled up the fluid in the HPU but then just stopped and hasn't worked since...

I checked the switch by jumping as indicated in the guide both at the switch and at the HPU and it acted as it should (just no movement)

Then I swapped the hydraulic lines and the problem persisted. The HPU makes noise and the starboard one works and the port doesn't move. So the HPU seems ok and the solenoid also appears to work.

My next step was going to be to unscrew the port actuator and run the HPU and see if I get anything coming out. The other end of the hydraulic line inside the transom is very hard to reach so this'll save a lot of cursing... I was hoping there was something simple blocking it and I could giggle and it would all work.

My questions are - is this the most logical step? Is there another step or check I can do?

I wouldn't be so hot to fix it but with a single o/b the boat twists a little to port and if the wind is right I get sea spray on the wife. "Happy wife happy life" :-)
Old 02-08-2014, 07:26 AM
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There are two solenoids on the hpu. You can do two things. Swap the wires on the solenoids. If the problem changes sides, you have a wiring problem. The plastic molex connector ( #32 in image below)before the pump has been known to be a problem and Bennett has recommended hard wiring it. The other thing is to swap the solenoids themselves and see it the problem follows. Tabman Tom may have the resistance in Ohms for you so you can check them with a multimeter. Good luck.
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Old 02-08-2014, 07:45 AM
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Thanks for the idea Mud Runner, and the schematic.

I swapped the hydraulic lines and the problem stayed on the dame side, which I "think" accomplishes the same thing but I'm not expert.. It seems to be between the motor and the actuator, or the actuator itself?

Wife wants to go to the beach so may get another stab at this today :-)
Old 02-08-2014, 09:20 AM
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Netjirk,

Do you know how old the system is? Also what type of boat is it on?

If you swapped the tubing and the problem stayed on that side then the problem is likely not with the solenoid valves. But just to be sure if you hot wire the blue and red wire right at the pump does the port Trim Tab go down? Also hot wiring the yellow and red wire should retract the port side.

Also make sure both ends of the black ground wire bat the pump are vclean and tight. Low voltage will cause the valves to operate poorly.

If you take the tubing of the front of the pump and operate it fluid should come out of it in a solid stream with no frothing or spitting. You can catch it in a container to do this test.

Have the actuators (rams) been removed from the boat for any reason? It is possible to screw the pipe nipple in too far (the part that goes through the transom) and it will block the fluid passage to the actuator.

If you put a hose clamp non the piston shaft and unscrew the lower hinge from the Trim Tab you can unscrew the cylinder body from the part that screws to the transom. The clamp keeps the piston shaft in place. This way you will not have to remove it from the boat. You can then see if fluid is running through the transom.

Let me know what you find and I will be delighted to help.

Tom Mcgow
Bennett Marine
Old 02-08-2014, 10:49 AM
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Hi Tom!

Thanks for your reply. The system is quite old I think. It's on a 1983 Wellcraft 248 Sportsman. The HPU model number is something like 3701... But I don't have the number in front of me so it's likely not that.

I am sure I hotwired as the instructions say and it didn't react any differently. The HPU actually sounds like it's trying to pump and is meeting resistance . When I swapped the hydraulic lines it was still no issue for the starboard side to move up and down while when I made the port side (then the opposite switch) go nothing happened but the pump sounding laboured.

I unscrewed the actuator (hose clamp... Genius!) and ran the pump and it squirted fluid out. I put it back together (I attach the spacer to the hinge and then screw the actuator on) but there was no difference.

I refilled the reservoir, tried it again and no change in effect. Could it be an issue in the actuator? I looked at the actuator schematic and it looks just the same.

Just to be absolutely sure tomorrow morning I'll take the dash off and hotwire again now that I've checked everything and the reservoir is full.

Any hints and tips are appreciated!!!
Old 02-08-2014, 12:08 PM
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Netjirki,

Just to be sure, hot wire right at the pump, not the switch. Also check to see if there is a small grey relay box in the wire harness right by the pump. If there is remove it and try again. The relay was used in older systems to prevent the fuse from blowing if you push one tab up and the other down at the same time (our switches prevent that now). If it works when you take it out then the relay is faulty. You can leave it out and run the boat.

Also, make sure that all 12 screws are clean and tight on the back of the switch, even if they don't have a wire attached.

Lastly make sure the port solenoid valve (red wire) is screwed in only finger tight. If it is too tight it could malfunction.

Tom
Bennett Marine
Old 02-08-2014, 12:43 PM
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Originally Posted by Tabman View Post
Netjirki,

Just to be sure, hot wire right at the pump, not the switch. Also check to see if there is a small grey relay box in the wire harness right by the pump. If there is remove it and try again. The relay was used in older systems to prevent the fuse from blowing if you push one tab up and the other down at the same time (our switches prevent that now). If it works when you take it out then the relay is faulty. You can leave it out and run the boat.

Also, make sure that all 12 screws are clean and tight on the back of the switch, even if they don't have a wire attached.

Lastly make sure the port solenoid valve (red wire) is screwed in only finger tight. If it is too tight it could malfunction.

Tom
Bennett Marine
Thanks Tom, I will try all of the above in the morning and report.
Old 02-08-2014, 01:57 PM
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Tom,

By swapping the hydraulic lines as I did and testing, am I wrong to think I've eliminated a switch issue?

I'll hotwire tomorrow morning before we go out and check for a relay. There is a unit the pulls them up when the key it turned off.

Thanks again Tom,

Kris
Old 02-08-2014, 03:01 PM
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Kris,

Yes I think you have eliminated the switch, but just check to make me happy

And double check the back of the switch to make sure all of the screws are tight.

It is really rare for the actuator to fail, but it can happen.

Check out what I listed in my last post and let me know!

Tom
Bennett Marine
Old 02-08-2014, 03:10 PM
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Tom,

Will do!

I used to work tech support and whenever someone would tell me "they already did that" I always made them do it again too. Usually worked after I made them do it again ;-)

Kris
Old 04-02-2018, 10:19 AM
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Default Bennett trim tabs issue wont extend

I have a 2014 Wellcraft 252 fisherman bought in 2015 with factory installed bennett hydraulic trim tabs. They have always work well but since a week or so they wont go down.

I did some testings, when I press any of the bow up switches I can hear the selenoids clicking and the pump working, so no problem with that. But when I press any of the Bow Down switches I just hear the selenoids clicking but the pump does not react, so the tabs wont move. This makes me think pump is turning to one side but not to the other. HPU is model V351.

Any suggestion with this technical issue, appreciate your help.
Old 04-02-2018, 12:37 PM
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Originally Posted by arrivillagao12 View Post
I have a 2014 Wellcraft 252 fisherman bought in 2015 with factory installed bennett hydraulic trim tabs. They have always work well but since a week or so they wont go down.

I did some testings, when I press any of the bow up switches I can hear the selenoids clicking and the pump working, so no problem with that. But when I press any of the Bow Down switches I just hear the selenoids clicking but the pump does not react, so the tabs wont move. This makes me think pump is turning to one side but not to the other. HPU is model V351.

Any suggestion with this technical issue, appreciate your help.
I would like you to try step 3 below both at the switch and at the pump also check to make sure all the screws are there and tight on the back of the switch too.

Let me know what you find,

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).
Old 04-02-2018, 01:45 PM
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Originally Posted by Tabman View Post
I would like you to try step 3 below both at the switch and at the pump also check to make sure all the screws are there and tight on the back of the switch too.

Let me know what you find,

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).

Thanks for your reply, I will be doing this tests by the end of the week. ill let you know.
Old 04-03-2018, 03:53 AM
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Very Good! I will be standing by!

Tom
Bennett Marine
Old 04-03-2018, 04:04 AM
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Tom, you mentioned fluid should not be frothy. When I run the pump without lines attached the fluid comes out frothy. What does, if anything, the frothiness indicate?
Old 04-03-2018, 04:16 AM
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Originally Posted by Thunderyacht View Post
Tom, you mentioned fluid should not be frothy. When I run the pump without lines attached the fluid comes out frothy. What does, if anything, the frothiness indicate?
There could be an air leak in the pick up side of the pump. If it's frothy and milky there could be water in the fluid.

How old is the system?

Tom
Bennett Marine
Old 04-03-2018, 05:33 AM
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Originally Posted by Tabman View Post
There could be an air leak in the pick up side of the pump. If it's frothy and milky there could be water in the fluid.

How old is the system?

Tom
Bennett Marine
It’s a 2001 aquasport so I assume it is factory installed then. Could the leak be around the fill tube cap? I always seem to have a little fluid coming from around that area and the cap is not tight at all. FYI, I pulled the pump and tested per your instructions last week and it works in all directions. I removed the gray box that was in front of the pump and pulled all new wires from console to pump and put a new switch in the console so all electric is good. Just frothy fluid and tabs won’t move. Must be air in the system.
Old 04-03-2018, 07:15 AM
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There is no pressure in the reservoir, so it really can't come out of the filler cap. The pickup tube comes out of the round pump body and goes into the reservoir below it. It may be cracked or damaged allowing air into the system. There is no real easy way to fix this. You can try examining it by removing the strap that holds the pump motor on top or the reservoir and pulling the HPU straight up.

Tom
Bennett Marine
Old 04-19-2018, 07:39 AM
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Originally Posted by Tabman View Post
Very Good! I will be standing by!

Tom
Bennett Marine
Back to you Tom.. went to the boat with an electronics technician and check everything as you indicated. Removed cables from switch having the following results:

Orange (+), blue, red= Port trim tab down............ Selenoid clicks but pump wont turn
Orange (+), blue, green=Starboard trim tab down.........Selenoid clicks but pump wont turn
Orange (+), blue, red, green= Both trim tabs down.......Selenoid clicks but pump wont turn
Orange (+), yellow, red= Port trim tab up .....................OK, selenoid clicks and we hear the pump turning
Orange (+), yellow, green=Starboard trim tab up..........OK, selenoid clicks and we hear the pump turning
Orange (+), yellow, red, green= Both trim tabs up ... ....OK, selenoid clicks and we hear the pump turning

went down to the bilge and check voltage on all cables right at the pump mainly the blue that turns the pump to lower the tabs, all receiving solid 12.4 volts, fluid level also ok
We conclude that the pump is turning to one side but not to the other and wont lower the trim tabs. Appreciate your assistance in what to do in this case,,
Old 04-19-2018, 10:27 AM
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The only thing you can try is to cut the blue wire (it runs the pump forward) out of the connector on the pump side, and see if the pump will run when you put 12v positive to it. Just to make sure the connection is not corroded. If it runs them splice the wires back together. If it does not run the pump will need to be replaced.

They have a 5 year warranty. Go here https://bennetttrimtabs.com/wp-content/uploads/2015/01/Bennett_Return_Form.pdf

Fill out the form and return it to the address on it, and we can replace it, please drain the fluid and place it in a plastic bag before sending it back.

Tom McGow
Bennett Marine

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