Bow Thruster didn’t work - cannot be activated

[miraculix]

Hi all,

Our boat is a Beneteau 40 2008. We have a MAX Power CT 80 bow thruster installed which has its own battery. We are in our third season with the boat and so far did not have any issues with the bow thruster. Yesterday we prepared the boat for a short sail and found that the bow thruster could not be truned on. The typicall ... press both knobs for a couple of seconds - hear a beep and so on did not work. The thing was dead.

I started hunting down the problem. First I checked the battery, which appears to be OK at least from a voltage perspective, 12.7 volt.
Then I dissasambled the switch in the cockpit and found that there was no voltage.
Then I got the manual out and looked over the bow thruster circuit. After that I went back to the bow thruster and tried to identifiy what I saw in the manual.
There was no voltage on the wiring harness that comes out of the Electronic Control Box and goes to the control panel. The same as at the panel directly. No luck here.

Then I realized a little box the former owner had left behind. In there were an "old" control box and multiple five pin relays.

I turned my attention back to the bow thruster and his wiring.

There is no electric battery isolator.

The battery switch was on.

The power fuse was intact.

The power cable going into the control box has no voltage.

According to the manual the voltage for the control box is supposed to come from a different power source - independent battery bank for control circuit supply. That should come from the Main DC Panel and have an 8A fuse. I followed the power supply cable from the Control Box backwards which goes to the relay I mentioned earlier. Exactly to Pin 87.

Now to the relay. The cable that goes into Pin 86 (coil) has voltage 12.9 V. From Pin 86 a cable loop goes to Pin 30, so Pin 30 has voltage as well. But wait a second doesn't that contradict the whole point of a relay?
Anyhow, with pin 30 (continuously) energized the relay should switch to Pin 87 and there should be voltage but there isn't.

So now I am somewhat confused as to what is going on here and why is there a relay?

The power for the control box should come for the main DC panel protected with an 8 amp fuse. Unfortunately, I cannot find anything on the main panel and the Beneteau manual is less than helpfull.

I now wondering if could just remove the relay and connect the power to the control box directly. The realy did not portect anything, it's just a switch, or am I wrong here? However, I am just afraid to do that, not sure if I could damage something? But how?

It would be nice to know where the 8 amp fuse is and where the power is exactly coming from. Any ideas here how to find this out?

Sorry for this lengthy post.

I am thankful for any input!

Christoph

 

[jssailem]

Hello Christoph

It would be nice to know where the 8 amp fuse is and where the power is exactly coming from. Any ideas here how to find this out?

I would get a bright flashlight, put on some knee pads and crawl around the boat looking in the dark holes that no one wants to explore and trace the wire.You indicated you thought you could see it at the controller box. The wire drawing suggests that is where it is connected. Check if it has power. Then follow it back to the power source.

if could just remove the relay and connect the power to the control box directly. The realy did not portect anything, it's just a switch, or am I wrong here? However, I am just afraid to do that, not sure if I could damage something? But how?

The relay is in your circuit (which appears to be different than the one in your wire diagram). The purpose is to use a low voltage /amp source to trigger (switch on/off) a high power function. The wires used by the relay would be supplying the controller. So I agree I do not know why the relay was installed as the controller should have an internal relay for that purpose. Note that the 2 grey wires go out of the controller to the MaxPower "Isolator", which you say you do not have. I believe they serve to switch on the main power to the thruster.

The power for the control box should come for the main DC panel protected with an 8 amp fuse. Unfortunately, I cannot find anything on the main pane

I agree and you are in a place to figure out how the system was installed using an alternate plan or go back to the original wire diagram and correct the wiring for your thruster.

I note in the wire diagram that there are 2 switches on the power switch. On on the load (red wire) and one on the ground (black or yellow wire) (typical of Beneteau electrical design) be sure both switches are functioning.

You may want to try and call Max Power support. They may be able to help clarify the wiring even if it is not how they specify.

 

[Davidasailor26]

That does appear to be a strange way to wire the relay. I wonder if the previous owner did something strange there that just caused the 8A fuse (wherever it is) to blow. I presume your thruster only works when the “ignition” is on? If so I wonder if the 8A fuse and power to the control panel comes from that circuit somewhere, rather than the house panel.

 

[DayDreamer41]

First question, is the thruster 24v or 12v? if 12V I am guessing the 8A control wire is fed from the same source.

 

[miraculix]

Hi

Thank you for your answers.
I apologize, I think I have not explained it very well. Sorry, English is my second language.

So I tried to trace the wire that brings the power to the bow thruster control box. I can trace it up to the house battery compartment but there it becomes really convoluted, so I have not made it further than that.

I may have explained that wrong. The wire has power 12.7 V. So there is power to PIN 86 of the relay, the coil should be energized and switch the relay. But… there is not power on PIN 30 and that is probably why there is that wired jumper cable that brings power to PIN 30. No power is coming out of the relay (PIN 87) so no power to is going to the control box what seems to be the issue.

The power for the “MONSTER” relay that is switching the power to the motor is coming out of the control box (brown and black) but the control box itself has no power and that is, at least I think because of this interesting relay that according to the wiring diagram is not supposed to be there.

BTW, I found multiple of these relays in a card box next to the bow thruster together with connectors and an old control box. There must have been issues that the former owner has solved or tried to solve. Most of the relays were used.

So now I could just bypass the relay and maybe good. But that leaves me with the question, is there something I do not know? Why is there this relay that doesn’t seem to have any “relay function”.

AND

Even there is power I would feel somewhat better to know where the power is on the panel where is the fuse.

I will continue to find the fuse … I just don’t want to smoke the control box

Thanks
Christoph

 

[miraculix]

The Thruster is 12V and the power is according to the manual not coming from the same source or better should not come from the same source.

 

[DayDreamer41]

Is there another red conductor for the center (87a) if not there needs to be one, otherwise the thruster would only work in one direction. It appear to me that the previous owner had an issue with the main controller and remidied the issue with the relay.

 

[SoSound]

The power for the control box should come for the main DC panel protected with an 8 amp fuse. Unfortunately, I cannot find anything on the main panel and the Beneteau manual is less than helpfull.

Do you know if this installation is unaltered from the factory? There a few components (bow thrusters, windlass, ENGINE BLOWER) in the electrical system that are wired (with relays, etc.) so that they will only operate when the engine is running. I'd have to dig through a post from several years ago for all of the details, but we had what we thought was an alternator failure while out cruising. We had a battery charge alarm go off while motoring. While on the phone with our dealer, troubleshooting the alternator, my wife insisted that I mention that our engine blower had also stopped running... that changed everything in our troubleshooting. The cause of both the alternator output and engine blower problems ended up being a broken wire connector at a relay near the alternator.

Also, if you are troubleshooting without the engine running, you may very well not get the voltage which activates the thruster circuit.

[Edit:] If the thruster was added by the previous owner, I'll just bow out here and watch this thread and learn.

 

[DayDreamer41]

Also, if you are troubleshooting without the engine running, you may very well not get the voltage which activates the thruster circuit.

Excellent question!

 

[miraculix]

The bow thruster was definitely installed in the factory. However, based on the box with "spare parts" that I have found next to the bow thruster it appears to me that changes were made and parts were exchanged.
As mentioned above the wiring diagram in the manual does not show a relay where there is now a relay. That maks me thinking what the intention was to put a relay there. The problem is that I have no idea whay these parts were not discarded. I found boxes in other areas with used electronic parts.

I guess I could just cut out the relay and I would have power to the control box. But I feel that I do not entirely understand what is going on here and I don't want to smoke the control box. Hence I would feel better to know where the fuse is.
Anyhow, I attached another picture that may better explain what I am talking about.

I had the engine running at one time but no luck.

 

[DayDreamer41]

Based on your drawing the relay is unnecessary, it may have been added to the circuit to ensure the motor was running before power was provided to the thruster, I say this as the wiring diagram you showed is direct from MAX Power's sight, if factor installed they may have added the relay to ensure the motor was running, the fuse may/should be a breaker on the main DC distribution possibly a push to reset type.

 

[miraculix]

Based on your drawing the relay is unnecessary, it may have been added to the circuit to ensure the motor was running before power was provided to the thruster, I say this as the wiring diagram you showed is direct from MAX Power's sight, if factor installed they may have added the relay to ensure the motor was running, the fuse may/should be a breaker on the main DC distribution possibly a push to reset type.

That is a good point. However, the way the relay is wired it will send voltage continuously to the control box. In addition the relay is a standard automotive relay which activates the circuit when the coil is energized with 12V nothing fancy here. There is 12.7 V without the engine running and 13.5 V with the engine running. There is voltage on Pin 30 and 87a but NOT 87 where the load should go out to the control box. Hence the relay doesn’t switch from 87a to 87 so no load going to the control box. I tested one of the multiple other relays that I found in a box next to the bow thruster, but no effect.
Here is a little diagram, I think I am going to put the wire direct to the control box without the relay. I don’t understand why this relay would make sense and it doesn’t seem to function as expected for a 5 pin relay. However, the whole setup has function during the last two seasons.

 

[DayDreamer41]

The relay would only make sense if the only time terminal #86 went hot with the engine running and terminal 87 or 87a went hot to complete the circuit to the thruster controller.

 

[miraculix]

The relay would only make sense if the only time terminal #86 went hot with the engine running and terminal 87 or 87a went hot to complete the circuit to the thruster controller.

That is what I was thinking.

 

[Capn John]

You may be chasing down the wrong path here. Do a Google search on "max power bow thruster heat sensor" and you will find several boat tech forum discussions and part sources for the heat sensor. The sensor is supposed to protect against overheating and shut down the thruster before damage occurs, but they rather frequently seem to just go bad for no reason. It actually fails to a closed circuit rather than an open circuit, and you can easily test for it by disconnecting the two yellow wires shown in your diagram above. If the thruster works with the yellow wires disconnected, it is the sensor that has gone bad. You can just unplug the sensor wire from the harness wire to disconnect it as shown below. But you should go ahead and replace it to maintain the circuit protection -- the good news if that is the problem is that you can get a replacement for just $25. I had to replace mine last year, so I took some photos. I have a CT100 but I believe all the Max Power thrusters use this sensor. Hope this helps!