Vetus bow thruster

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Dkk3000

Veteran Member
Joined
Jun 19, 2018
Messages
64
Location
US
Vessel Make
1987 Grand Banks 36 Classi
I’ve got a grand Banks 36 classic with a Vetus bow thruster model number BOW50112. The solenoid went bad and the bow thruster stop working. I bought a very similar solenoid from the auto parts store and hooked it up and I’m getting no power to the thruster I’m wondering if anybody has had this issue or is it a special solenoid? It is not the solenoids in the main unit, but looks to be one in front of that. It’s a aftermarket installation. I can jump. The two large cables and it will work. But I’m having no luck with this aftermarket solenoid. I have attached a picture of both solenoids. The one on the right is the one that came with the unit or was installed before I purchased the boat.
 

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Appearance is not a good way to find a suitable replacement. I suspect the key specs you need to screen for are:
1) voltage 12v?
2) current rating. Thrusters are high current draws. Find the max amperage draw on your thruster (specs should be online)
3) as far as I know most thrusters will provide a reversible output. This will change how your motor spins to move port or starboard
4) I would probably stick with one built for the marine environment. Often they are in high moisture environments with salt exposure unless you are in fresh water.
 
It sounds like a bad solenoid due to the fact that you can jump it and it works. OR you have a bad connection at the switch that operates it.
 
The two little posts are for the control signal. You should have 12 volts there to close the relay.
I take it that this is a remote disconnect? There should be a switch to operate it. Maybe that is bad or doesn’t have any power.
 
The two little posts are for the control signal. You should have 12 volts there to close the relay.
I take it that this is a remote disconnect? There should be a switch to operate it. Maybe that is bad or doesn’t have any power.
Should I have 12 V at both of the small post. The other thing I was thinking, it might be a bad control module at the helm. Does that sound like a possibility?
 
No, one is 12V, the other ground. Polarity not important. If wired this way should "click" when powered, no need to attach high current cables for this test.
 
So the original solenoid went bad and the new one is also bad? Maybe the original wasn’t really bad but the problem is elsewhere.
 
So the original solenoid went bad and the new one is also bad? Maybe the original wasn’t really bad but the problem is elsewhere.
You could be right on that, the original solenoid, where the main power lead from the bow, thruster hooks onto it, it was totally fried and loose. I just assumed that the solenoid was bad. Now I’m thinking the new solenoid which I bought at an auto store, may either not be the problem or the wrong solenoid. The question I have is II don’t know why I got an external solenoid on the bow thruster when it has two built-in solenoids already. This was an aftermarket installation. Any ideas?
 
The extra solenoid seems like it’s not needed, but was installed as a remote disconnect. If there’s a manual disconnect switch you might want to just bypass it.
That would be your call.
Where and what type of switch turns it on? Do you have a volt meter and know how to use it?
 
Thanks for the quick reply, I’ve got a breaker on the panel that turns it on or off. I’m thinking that that’s probably the remote cut off switch that you’re referring to. I’ve got two stations one in the salon one at the helm that operates the bow thruster with an on off switch. The way they’ve got the breaker set up, is that it turns on both the winless, and the bow thruster. Which I can sort of understand, but probably not the proper factory set up. I do not have a fuse anywhere in the cable from the battery to the bow thruster. Usually they have like a blade fuse close to the battery. I do have an amateur and pretty familiar with the electrical stuff. Again, thank you for your quick reply. I was up at 2 o’clock in the morning trying to figure this thing out so I can use the boat this weekend.
 
Correction, that was supposed to be voltmeter not amateur.
 
The solenoid that was on the boat, or the bow thruster, is a four pole solenoid. It is not grounded to the chassis, so I’m assuming that the two small post would be the ground and the hot . Should I be able to apply external 12 V power to the solenoid or the new solenoid that I bought and at least get a click or activate the bow thruster?
 
Ok, I was thinking of the solenoid as a remote disconnect. The switch on the breaker panel is for activating it.
So yes, apply 12 volts to the two small posts and the solenoid will close allowing you to use the thruster. It doesn’t matter what post is positive or negative.
Alternatively, you can put in a on/off battery switch for a disconnect. That would require you to switch it manually, but it would be reliable.
To troubleshoot the existing setup, get behind the breaker panel with the voltmeter and check to see if the breaker has 12 volts on its output terminal when you switch it on. If that’s good, I’d go to the solenoid and see if there was a good ground at one of those little posts. Meter leads on the battery side of the big cables at the solenoid and one of the small posts. Hopefully you can see which wire should be the negative. Tons of problems are a result of bad grounds.
If the ground is good, there’s an issue with the hot wire coming from the breaker. Pretty simple actually.
 
OK I will do that today, the other question is, what kind of solenoid should I get. I believe what they sold me, was a solenoid for an automotive starter. They usually are grounded to the chassis and the two small post are for the ignition switch and usually a coil . Do you have an idea or can you send me a link of the proper solenoid I need that has the post for the ground and the other post for the hot. Like I mentioned before, this solenoid is not mounted to any grounded chassis part.
 
OK I will do that today, the other question is, what kind of solenoid should I get. I believe what they sold me, was a solenoid for an automotive starter. They usually are grounded to the chassis and the two small post are for the ignition switch and usually a coil . Do you have an idea or can you send me a link of the proper solenoid I need that has the post for the ground and the other post for the hot. Like I mentioned before, this solenoid is not mounted to any grounded chassis part.
Virtually all of those solenoids are the same. Some carry higher current than others.
When they’re chassis mounted, there’s a small jumper wire from one of the small posts to the mounting bolt. That’s where the negative side comes from. Then, the other small post comes from ignition/start signal. If there’s a coil hookup there too, it’s usually for providing 12 volts to the coil during cranking, bypassing the ballast resistor. It just gives hotter spark during cranking. It would be on the same post as the start wire.
Anyway, the solenoid is just a simple relay. Put power to the small posts, positive on one, negative on the other, and the relay will close, allowing power through the big posts.
 
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Just for your reference, the solenoid on the right is the one that I believe went bad, and the one on the left is the one that I bought from the auto store. If you look at the old solenoid on the left battery lug , you’ll see where it got extremely hot and melted that terminal
 
Just so I understand what you’re saying. On the new solenoid, I can apply 12 V and a negative and it should energize the coral and I should get continuity between the two battery lugs
 
Yes! Thats why I mentioned a bad connection or solenoid. So maybe a foot switch, panel switch is bad or a connection. If 12v does not reach the 2 small post on the solenoid, its not going to work.
 
OK, I understand what you’re talking about. I will check voltage from the panel breaker and make sure I’ve got voltage going to the solenoid. I think that will tell me a lot right there. I’m thinking, the way they’ve got it wired, is the hot from the panel breaker goes to the control unit and then it goes to the solenoid that would probably be the only way it would work. In other words, when the power is on at the breaker, when you turn on the control unit and hit the thruster at that point the power has got to go to the solenoid. Does that sound correct?
 
The solenoid is a magnetic switch. You apply 12v, the coil becomes a magnet pulling it to make contact with the 2 big cable from within. Just to keep it simple.
 
Thanks everybody for all your help. I’m going out to the boat tomorrow. I will keep you updated on what I found out. Again thank you very much.
 
To verify when you get there, ohm out the small terminals and should be some resistance (the coil) and make sure there is no connection to either the frame or the big lugs. If so then it's a standard type with the coil between the smalls and the 2 big lugs get connected when it clicks (pulls the internal bar across the 2 big lugs)

These things are really simple.

Yeah, you had some serious overheat on the old one either to a bad connect on the lug or a bad connect inside the solenoid.
 
Those solenoids have a duty cycle you should pay attention to. Thrusters take a huge amount of power, extended run time may overheat a solenoid like that.
Those devices come in different amp ratings too. I’d look up the specs on the new one to see what it handles.
 
Well, I’m back on the boat, as far as the solenoid goes. It looks like it’s an automotive starter solenoid. If I ground the chassis of the solenoid externally to a ground and run the one hot wire from the breaker, it works fine.
 
i’m using the same ground wire that was originally on the old solenoid. I just put a ring terminal on it and grounded it to the chassis on the solenoid.
 
Everything works the way it did before however, the solenoid seems to be getting hot. That’s my only concern.
 
it’s obvious to me that the old solenoid had a ground at a hot on the two terminals. I just don’t know what to look for as far as trying to buy one of those. I’m pretty certain the new solenoid is a automotive starter solenoid with one terminal hot coming from the ignition switch and the other one going to probably a coil or something
 

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