trim tabs not working

gator79

Petty Officer 2nd Class
Joined
Jul 13, 2003
Messages
106
I have bennett trim tabs with the auto tab controller and they are not working. I have voltage to both of the auto tab computers. does anyone know how to diagnose this system? Tabman? :confused:
 

Tabman

iboats.com Partner
Joined
Feb 21, 2002
Messages
566
Re: trim tabs not working

Gator,<br /><br />I am sorry to hear that you are having a problem with your system, lets get it fixed! <br /><br />If both systems are non-responsive we need to check the black ground wire (at the pump and at the ATC). Check the Tabs ground first since getting the Tabs to function will help diagnosing the ATC. Also check the Tabs 20 amp fuse, as well as the 20 amp and 1.5 amp fuse for the ATC. You might find the installation instructions for the Tabs http://www.bennetttrimtabs.com/online.html and ATC http://www.bennetttrimtabs.com/onlineatc.htm helpful in locating the fuses and grounds.<br /><br />If the fuses and grounds are OK then use the Troubleshooting below to check out the system and let us know what you find.<br /><br />Tom McGow<br />Bennett Marine<br /><br />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.<br /><br />Fuse: 12 volt system use 20 amp in-line fuse on positive. (24v & 32v use proportionately smaller)<br /><br />Red= Port Valve <br />Green= Starboard Valve<br />Blue=Motor Forward (pump pressure)<br />Yellow= Motor Reverse (pump retract)<br />Black on HPU=Ground<br />Orange on Helm=Control Positive<br /><br />Troubleshooting<br /><br />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<br /><br />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.<br /><br />3. Conduct the following test:<br /><br />Remove the wires from the helm control and touch together as follows:<br /><br />Operation=Reaction<br />Orange (+), blue, red= Port trim tab down<br />Orange (+), blue, green=Starboard trim tab down<br />Orange (+), blue, red, green= Both trim tabs down<br />Orange (+), yellow, red= Port trim tab up<br />Orange (+), yellow, green=Starboard trim tab up<br />Orange (+), yellow, red, green= Both trim tabs up<br /><br />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.<br /><br />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.<br /><br />4. If you suspect corrosion on the wire connector near the pump, cut it out, test as above and reconnect using butt splices.<br /><br />5. If you conclude the problem is in the pump, contact me. Bennett Trim Tab Systems carry a five year warranty. We also offer a trade in program for units out of warranty. Contact us for further details after you troubleshoot the system.<br /><br />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. If it works the IR1000 will need to be replaced.
 

gator79

Petty Officer 2nd Class
Joined
Jul 13, 2003
Messages
106
Re: trim tabs not working

thanks I will test and get back with you
 

gator79

Petty Officer 2nd Class
Joined
Jul 13, 2003
Messages
106
Re: trim tabs not working

ok the ground wire was disconected. now the tabs work with the switch, but auto tabs do not work.<br />when you push the on button on auto tabs it lights up for a second and then the controler makes a clicking noise like a relay disengaged and the light goes off. also when you work the tabs manualy the lights on the auto tab control panel flash on for a second when you release any button. any ideas?<br />thanks
 

Tabman

iboats.com Partner
Joined
Feb 21, 2002
Messages
566
Re: trim tabs not working

Gator79,<br /><br />Ther is a 4 color wire harness that pluge into the top box (ATC Module). Please try unpluging it from the ATC Module and see if the Auto Tab Control will stay on when you turn it on. If it will not stay on I belive we should replace the ATC Module, if it does stay on we need to replace the manual Trim Tab switch (even if it works the Tabs OK).<br /><br />Do you know who old the system is?<br /><br />Tom McGow<br />Bennett Marine
 

gator79

Petty Officer 2nd Class
Joined
Jul 13, 2003
Messages
106
Re: trim tabs not working

yes it does stay on with the 4 wire conector un pluged.it make a series of three clicks with it unpluged. the system is installed on a 1979 Grady White 24 offshore. the trim tabs were standard on this model. not sure if the auto tabs were added at a later date. it has the 4 button racing style switch. thanks for your quick response.
 

Tabman

iboats.com Partner
Joined
Feb 21, 2002
Messages
566
Re: trim tabs not working

Gator79,<br /><br />It sounds like the manual Trim Tab Switch has a slight short somewherwe that is affecting the ATC. If the ATC will stay on an not shut off with the four color harness unpluged it means that the ATC is "seeing" voltage comming from the switch and turning off. It would be like the cruise control in your car sensing the brake is on and shutting off. You can try cleaning the back of the switch wit contact cleaner and see if that solves it, if not then the Switch will need to be replaced.<br /><br />Tom<br />Bennett Marine
 

gator79

Petty Officer 2nd Class
Joined
Jul 13, 2003
Messages
106
Re: trim tabs not working

also how do you check the fluid level?
 

gator79

Petty Officer 2nd Class
Joined
Jul 13, 2003
Messages
106
Re: trim tabs not working

yes the light stays on. but it makes a clicking noise from the ATC. is that normal with the 4 wire conector unpluged?
 

Tabman

iboats.com Partner
Joined
Feb 21, 2002
Messages
566
Re: trim tabs not working

Gator,<br /><br />To add fluid: With trim tabs completely retracted, fluid level should be about 2” from bottom of reservoir (approximately 22 ounces).<br />To refill, remove lexan cover and filler plug located at the front left hand corner of the reservoir. FILL WITH ANY TYPE AUTOMATIC TRANSMISSION FLUID (ATF) ONLY. Brands or types of ATF can be mixed. Running HPU with<br />an excess or lack of fluid will not cause damage.<br /><br />Go to this page at our website to download an owners manual for the Tabs http://www.bennetttrimtabs.com/ownman.pdf The clicking noise is likely normal as the sytem is sendinf commands to the Tabs through the relays in the ATC Modual and you hear them clicking. <br /><br />Tom<br />Bennett Marine
 
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