Bennett tab issue

redneck joe

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Had the engine pulled for a transom rebuild and one of my tabs is not actuating. I can hear the pump both when I hit the switch as well as the auto up but nothing happens.

Unit about three years old, worked fine until the engine pull my mechanic said he saw them both working after the reinstall a couple weeks ago.

Any ideas?
 
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seadogmike

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When the tab is activated there are 2 things that need to happen:
1. the pump has to come on and start pumping
2. A valve has to open that controls the direction of the fluid to the tab. (Up/Dn)

My guess since you say the pump is working (and is pumping because the other tab works) that the valve is not opening.
Somewhere I have the schematic for the Bennett Tabs. I will see if I can locate it.
 

Tabman

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Had the engine pulled for a transom rebuild and one of my tabs is not actuating. I can hear the pump both when I hit the switch as well as the auto up but nothing happens.

Unit about three years old, worked fine until the engine pull my mechanic said he saw them both working after the reinstall a couple weeks ago.

Any ideas?

Joe,

It sounds line the valve for that side is not opening, it could be a switch or wiring issue.

Take a look at this video https://www.youtube.com/watch?v=P3zmpXsuaH0

Then take a look at step 3 below, it will walk you through the test I think will isolate your problem. Make sure that ALL the screws are tight on the back of the switch even if they don't have a wire attached, this could be your problem.

Let me know what you find and I will walk you through fixing it.

Your system has a 5 year warranty so you are covered.


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).
 

seadogmike

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Sorry, While I was looking up some info, and found the video, you posted. Didn't mean to repeat the post.
 

redneck joe

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Update.
Being I really really hate electricity so I checked some mechanics first. I disconnected the ram at the tab ? the tab moves freely and I can put my weight on the piston and put it out a bit. So nothing jacked up outside the boat.

I then swapped the lines at the pump as suggested and port still not working. I noticed when I hit the port switch it almost immediately sounds like it is in full down ? the pumps strains like starboard side when it is all the way down and when I hit port up it almost immediately sounds ?bubbly? like its full up. No kinks on the run to the transom.

I don?t trust my old decrepit gauges - showing just under 12V when not running but I have two batteries hooked up with switch on 'all' and has no problem kicking over a 350 Chevy motor and this was acting this way while underway so was getting charged.

Pulled the switch, loosened wires and wiggled a bit in case a spot of corrosion hit. Same. Disconnected the wires and interestingly the steps listed really did not work. At the time of the disconnect, the starboard was down and could not get to go up. I eventually used the 'both up' step and it then came up.
I reconnected the wires to the switch and all worked as before (port not working as before).

Full confession I did not watch the video prior to going so did not do the solenoid check. I?ll go back in a bit and do that and report back. In the meantime?



***New issue - Went to the pump and noticed a leak. Cleaned up and ran a few more times. Seems to be coming from under the pump but above the reservoir. This is probably unrelated as last season I had to add fluid but at the time the bilge was so dirty I didn?t see any leak areas I figured it was at the transom and knew I was going to have that done so just added fluid and finished the year. Now that I have had a transom replaced the bilge is clean and can see the leak at the pump. The reservoir is (now) just below the view window. Forgot my glasses and could see where a fill line might be. So this is probably not related to current issue ? but what to check on this?
 

redneck joe

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Next update.

Solenoids check good ? one clicks quieter than the other similar to the video.
I disconnected line from pump to transom and was able to blow thru.

Leak seems to only be coming from the port side when I actuate ? I ran the starboard up and down a couple times almost zero fluid (may have been leftovers) to a lot when trying to running port up/down a couple times.

Could a blockage / leak be at the reservoir to the pump?
 

Tabman

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Joe,

Not likely.

Did you do step 3 as I mentioned? If you do it right at the pump and also at the switch it will tell us a lot.

Let me know
 

redneck joe

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I did at switch only. Do i have need ti do at pump as well but that should have nothing to do with the leak?
 

Tabman

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Did both Tabs work when you did test 3 at the pump?

Regarding the leak, we should replace the pump since it is under warranty. Where are you located Joe?
 

redneck joe

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No sir it did not and as stated even the one that 'works' did not come up. Ill pm you my address.
 

Tabman

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If you can, can you try it at the pump? I want to make sure replacing it will completely solve the issue. Then we can see about replacing it.
 

redneck joe

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10 4 will do in the am we just got back from a quickie weekend in guntersville and my body needs to rest. Cant run with the younguns like i used to.
 
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Tabman

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I hear you Joe :)

I also sent you a PM about the warranty. Let me know what you find.

Tom
 

redneck joe

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Sorry took so long, had to make a day trip to my Chattanooga shop and then wanted to throw the charger on the batteries to make sure there was not a low voltage issue, which there was but by redoing step #3 the switch is working ok (port still not working but starboard is). The test at the motor returns same results as at the switch. So am I assuming it is isolated to the pump?


Here is the amount of fluid after one up/down attempt.


 

Tabman

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Yes it is in the pump. We can replace it under warranty. Did you get my PM with the instructions for replacement?
 

redneck joe

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Thanks Tom - ironically came in yesterday while I was out on the water.
 
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