Last night the bow thruster went off on its own

[DavidJ]

On my boat for the first time in a few months and at about 2pm my bowthruster decided to go off. I switched off the power battery then switched on again and after a minute or so it went off again. I can make the thruster go right and left by using the toggle then it takes over on it’s own. The thruster is an original Volvo one.
its now 2:12pm and I’m going back to bed with the power off.
What could it be??

 

[LittleSister]

Perhaps with you having not been to the boat for so long, it's got in the habit of going out on its own.

 

[elton]

Water or condensation in the wiring or electronics.

 

[Assassin]

Faulty relay.

 

[jrudge]

Disconnect the helm controller.
If that stops it that is the fault. If not then it is either the thruster relay or wiring.
next disconnect the control wires from the thruster. Stops. It’s the wiring.
doesn’t it’s the thruster solonoid.

 

[stranded]

I had exactly this with my lewmar thruster last year. It was the helm control panel. No obvious water ingress but all potted so hard to know exactly what.

 

[DavidJ]

Thanks guys. I’ve just woken up to all your replies and will test out this morning. I guess you spotted my pm/ am mistake. It was very early in the morning.
Just switched the power on and of course all is OK. It’s one of those intermittent problems. Ahhhhh!

 

[DavidJ]

Took the toggle assembly off. Interesting arrangement, the plug is actually the switch.
Now would this go to a relay before going to the bowthruster solenoid.
By the way it had one more self thrust this afternoon, of course it self cured temporarily

 

[Croftie]

If its any help I am sure that the brown wire is the common wire, Link it to the white and the motor goes in one direction, connect to the green and the motor goes the other way. The actual relay/contacter is attached to the motor with just the three wires between the switch/plug and the motor assembly

 

[SimonD]

You can just see in that picture the black plunger. Push the joystick one way and the white pins move in to push the plunger in, the other way allows the spring in the switch to move the plunger out. The middle position is off. Not saying this is your problem, but the plunger can get stuck in. A bit of WD40 and working it in and out will give more reliable operation.

 

[DavidJ]

I’m going to disconnect the brown wire and see if it self thrusts. If it does then it’s definitely the solenoid end.

 

[DavidJ]

You can just see in that picture the black plunger. Push the joystick one way and the white pins move in to push the plunger in, the other way allows the spring in the switch to move the plunger out. The middle position is off. Not saying this is your problem, but the plunger can get stuck in. A bit of WD40 and working it in and out will give more reliable operation.

Thanks Simon
Good call, however the plungers do seem to be quite free and there is a little movement before contact is made so all seems to be ok for that bit. I will treat it to a bit of lube for the first time in 20 years

 

[tico]

Looks like a pretty standard GE joystick switch withe switch part available from electrical wholesalers without paying the BAT (boat added tax)

 

[DavidJ]

I’m going to disconnect the brown wire and see if it self thrusts. If it does then it’s definitely the solenoid end.

Just adding to my own thread.
If I get say a good period without a self thrust does that necessarily mean it’s the toggle switch or have I just disabled another cause.

 

[jrudge]

Rather depends why it went off in the first place. If a wire is chafed a d it goes on with the movement of the boat for example.

 

[CLB]

QL bowthrusters have been the cause of quite a few fires. (you said Volvo so I am assuming it is QL). They do seem far worse than other makes for suddenly doing their own thing, the result of which has, on a few occasions, been a wrecked boat.

 

[vas]

pretty sure (although it's some years when I installed mine) that the piece with the three wires does come off the main part. I also think you can have a look and clean contacts in there before reassembling
Mine has a small push button toggle that isolates the brown so b/w wont work unless I press that button again. Maybe worth installing one

V.

 

[DavidJ]

Mine has a small push button toggle that isolates the brown so b/w wont work unless I press that button again. Maybe worth installing one

V.

I’ve gone about 6 hours now without any self- thrusting with the brown wire disconnected. Assuming tonight doesn’t bring about any surprises, I’ll buy the QL 41100743 which is the replacement for mine. Reassuringly it has the small isolating button that you mention. Even if I haven’t traced the exact fault, I’ll feel like I’ve made a worthwhile upgrade.

 

[vas]

fwiw, ANY b/t control will do, I have the QL one and on the upper helm I have something else, I think sidepower, basically it's a two sided toggle with a nice fancy rubbery stick
try to open and clean the existing one, and anyway keep it as spare

V.

 

[Croftie]

fwiw, ANY b/t control will do,

V.

Just a word of caution on this, the Vetus one is a 4 wire and would not be suitable as think they include a time delay curcuit