Not sure tabs are working

[k9medic]

I have a 420AC and just had it put back in the water after a bottom job. While bringing it home on a 65nm run today it appeared that the tabs were not working.

Any ideas where to start and how to check this? I did check the circuit breaker and it felt as though it was tripped (but wasn't popped entirely out) so I reset it.

 

[dpmulvey]

I have a 420AC and just had it put back in the water after a bottom job. While bringing it home on a 65nm run today it appeared that the tabs were not working.

Any ideas where to start and how to check this? I did check the circuit breaker and it felt as though it was tripped (but wasn't popped entirely out) so I reset it.

Are you "sure" they aren't working?

Check for actual motion. If there is no motion, check for power to the back of the breaker. If there is power there,then to the switches and so on.....

 

[Tabman]

Start with what Mpmulvey said, and I would add check both ends of he black ground wire at the pump.

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

If you are sure they are getting power and not working then you can use the troubleshooting below.

Also we have a full troubleshooting video library to cove specific issues such as pump running, but tabs not moving and other faults, here is the link http://www.bennetttrimtabs.com/videolibrary.php

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

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).

 

[k9medic]

Thanks all. I will be back on the boat Saturday and will run through the items.

 

[dwna1a]

First and foremost, do everything Tabman said to do! He is the one person to go to for Bennett Tabs!

now, I've got to ask this one question. When they did the bottom paint, did they paint the pistons and tops of the tabs? I just saw a job done yesterday that they had painted the tops and hinges as well as the pistons. We had to use a soft hammer to break the hinges loose and remove the pins that hold the piston to the tap to free up the piston rod. Good luck!

 

[k9medic]

I'm not sure if they painted the tab pistons or not. It was back in the water before I had a chance to look at it.

I did find that the reservoir was completely empty and it appears that the fluid was sitting in an aft bilge area. After filling it back up with ATF I could hear the assembly "click" when the tab buttons were pushed but it didn't sound like the HPU motor was running.

Now I need to figure out where the leak is and how/why the motor would not make noise.