Beneteau 12v issue

[David 01]

Hi hope somebody could please shed some light on this peculiar situation.

My shower drain pump wouldn't work when I went to switch it on.
There is 13.5v in the wires going to the pump, soon as I switch the pump on the voltage drops to 0 volts, I assumed there must be a fault with the pump so purchased a new one but exactly the same issue, any ideas what the issue could be?
Many thanks.

 

[KevinV]

Dodgy connection somewhere - it'll show the voltage at 0 amps, but won't flow any amps

 

[VicS]

+1.
A very poor connection somewhere.
Check fuse for good contact and the isolating switch if there is one but could be any connection in the wiring including the negative.

 

[William_H]

As said a digital volt meter will test voltagee while drawing very little current. (it can smell the voltage even through a corroded joint) Best test arrangement is to fit a 12v bulb in parallel with meter leads that draws maybe an amp or so. This will be a more realistic test of voltage available. Or just test voltage with pump connected and supposedly working. Start at supply end checking to see how far voltage gets with a load on it. if you take your meter negative to battery neg. then use the (extended) positive lead to follow voltage from source to pump. If that is ok then fault is in the negative line do same with pos lead on pos battery terminal. ol'will

 

[Knig]

Hi Dave, a couple of questions.
Has this pump got a float switch and/or a direct on/off?
Where are you measuring the voltages and putting the probes?
Nigel

 

[David 01]

Thank you for all your replies,
William H, yes I put a 12v light bulb on the wires that would connect to the pump and the same happens, drops to 0v no light from bulb, unfortunately the wire runs right through the boat wrapped up with other wires behind pipes, pumps other wires etc so to rip it all apart will be a nightmare so I am thinking of just running a new power source to it from the main water pump, to make my life easier.

Nigel, hi, no float just a direct switch to turn it on or off, I am measuring the voltage at the wire connections for the pump, I've also cut these wires incase it was the plug but still the same, the black water tank 12v pump for pumping overboard is soldered onto these wires also a few inches down and this pump isn't working either with same results with a multimeter.

 

[greeny]

In my previous boat (Beneteau) I had a similar volts drop on the supply to the steering pedestal. I found the problem in the back locker where the supply wire was jointed to run a second wire to the auto pilot. Fortunately, although it was wrapped, there were only a few wires in the wrap and I could see the bulge where the connection was made. In the end though I finished up running two separate wires from the supply to the end devices to remove the connection from a cold damp locker. The faulty connection was a solder joint, insulated and hidden in the wrap.

 

[David 01]

In my previous boat (Beneteau) I had a similar volts drop on the supply to the steering pedestal. I found the problem in the back locker where the supply wire was jointed to run a second wire to the auto pilot. Fortunately, although it was wrapped, there were only a few wires in the wrap and I could see the bulge where the connection was made. In the end though I finished up running two separate wires from the supply to the end devices to remove the connection from a cold damp locker. The faulty connection was a solder joint, insulated and hidden in the wrap.

Thanks for your reply, funny enough the black tank pump is soldered into the wires and wrapped aswell, I will have a look there and see, thanks.

 

[Knig]

Hi Dave, are you saying that you measured 13.5v at the pump before switching on, or was it measured at the switch panel?
How is the black tank pump switched and where is the switch?
Nigel

 

[David 01]

Hi Dave, are you saying that you measured 13.5v at the pump before switching on, or was it measured at the switch panel?
Nigel

Hi Nigel, yes at the pump end, both shower drain out pumps run off the same switch on the switch board, the rear shower pump out works as normal in the shower at the rear of the boat the shower pump at the front of the boat is the faulty one.

 

[Knig]

The new pump is good isn't it ?

 

[David 01]

The new pump is good isn't it ?

Cable won't power a 12v bulb either unfortunately

 

[William_H]

Thank you for all your replies,
William H, yes I put a 12v light bulb on the wires that would connect to the pump and the same happens, drops to 0v no light from bulb, unfortunately the wire runs right through the boat wrapped up with other wires behind pipes, pumps other wires etc so to rip it all apart will be a nightmare so I am thinking of just running a new power source to it from the main water pump, to make my life easier.

Nigel, hi, no float just a direct switch to turn it on or off, I am measuring the voltage at the wire connections for the pump, I've also cut these wires incase it was the plug but still the same, the black water tank 12v pump for pumping overboard is soldered onto these wires also a few inches down and this pump isn't working either with same results with a multimeter.

On my little boat I had a wire battery to switches running under carpet at side against the bunk base. Had a power failure and fond power at one end of wire and none at the other end. Eventually found about midway the wire insulation had a bulge. Further investigation the insulation had been punctured and corrosion got in. Breaking the electrical connection. Had me baffled for a while. So yes if you have power at one end of wire and none a the other end bypass or replace wire. ol'will