Trim tab pump and control

[Steve cason]

Hi all.
I have a Bennet trim tab hydrolic pump running the one trim tab in my centurion wake board boat. It is controlled by a Protrim blinker style switch.

I have had electrical gremlins in the boat that I was finally able to isolate to the trim motor. When it is unplugged (remove both ground and the 4 pin connector), everything works great in the boat. However, when it’s connected I get a significant voltage drop at the helm (on the boats voltage gauge as well as when measuring with multi meter at the fuse buss).

I figured that the problem was a bad pump, and replaced the pump. However the problem got worse…. In fact some of the wires in the helm are actually hot to the touch…. Seems to me to be a huge ground loop problem on the circuit controlling the pump.

Between the blinker style Switch and the wires going to the pump, it was installed with 2 diodes so that the green wire is positive when either yellow or blue are. Logically, this is right… but I’m wondering what could be going wrong. Or if the diode method is right…

I have not yet checked continuity on the switch or voltage drops along that circuit…. That’s next..

Any help is appreciated.

See pictures.

 

[04fxdwgi25]

I haven't figured out the reasoning for the diodes. Need to find
the info on that controller.

 

[Steve cason]

Sounds like when it was wired, the huge load the motor draws was powered through the dash wiring. The dash wiring should only power the relays and the motor load (big red wire on pump) comes off the battery.

I think you’re right. I can’t find any relays in line with this circuit.
However, the voltage drop happens even when the switch is open, and the motor is not engaged…. So I don’t know if this could be the cause of the problem…

 

[04fxdwgi25]

Here is what the colors are for on the Bennett System:


I have yet to find the wiring for that ProTrim switch to try to figure out what was exactly done using the diodes..

It would seem as though the proper way would be to disable either the port (red) or stbd (green) circuit and use the other circuit along with the deploy (blue) and retract (yellow). That picture is very confusing, not knowing where those wires are going.

 

[04fxdwgi25]

I think you’re right. I can’t find any relays in line with this circuit.
However, the voltage drop happens even when the switch is open, and the motor is not engaged…. So I don’t know if this could be the cause of the problem…

Disregard what I posted earlier. That assumption was not correct.

 

[04fxdwgi25]

I see what is going on here. Here is the ProTrim diagram.

The green is down (deploy) and the blue wire is up (retract). If either the up or down are powered, the diodes power the stbd circuit.

Green from the ProTrim is down - connected to pump blue (deploy)
Blue from ProTrim is up - connected to pump Yellow (retract).
Either one being powered, also powers the stbd hydraulic port, through the diodes. Red from the pump should not be connected to anything.

What is that Red wire connected to?

Hope this helps.

PS: that circuit powering the Bennett pump should be on a 20 amp circuit separate from dash wiring ( straight to battery)

 

[Steve cason]

I see what is going on here. Here is the ProTrim diagram.
View attachment 383933
The green is down (deploy) and the blue wire is up (retract). If either the up or down are powered, the diodes power the stbd circuit.

Green from the ProTrim is down - connected to pump blue (deploy)
Blue from ProTrim is up - connected to pump Yellow (retract).
Either one being powered, also powers the stbd hydraulic port, through the diodes. Red from the pump should not be connected to anything.

What is that Red wire connected to?

Hope this helps.

Thank you. Yes. You are correct.

The red would be going to the center post in your diagram powering the green or red depending on the position…

The real problem starts there…. Why would I be experiencing a significant voltage drop?

 

[04fxdwgi25]

That red wire from the Bennet should not be connected to anything. The red wire from the ProTrim should go to a 20 amp fuse powered from the battery. The voltage drop comes from that Bennett red wire circuit goes through solenoids.

That is where your problem lies, me thinks. I will make a drawing on Visio for you and get back in a little bit.

 

[04fxdwgi25]

Here is what I believe should be:

Also, Add some shrink tubing over those diodes / connections to prevent short circuits and bigger problems

Also again: Make sure that port connection for hydraulic line is securely plugged on front of pump.

 

[Steve cason]

Here is what I believe should be:
View attachment 383934
Also, Add some shrink tubing over those diodes / connections to prevent short circuits and bigger problems

Also again: Make sure that port connection for hydraulic line is securely plugged on front of pump.

Thank you. This drawing is how I believe it is currently connected. However, there isn’t any heat shrink over diodes…. And possible that there was a short on the bare wires….

Also possible that the ground is bad on the circuit…. Today, I’m going to check continuity of the switch (in open position) to make sure it does in fact completely open, and voltage drop across the length of all those wires. My suspicion is that either one of those diodes is bad, or the ground wire is bad, or the switch is bad. Those are the only things I can think of that would make an ongoing problem like I’m having.

Thank you for the help. Let me know if you have other thoughts.