Pump wiring problem

[mcanderson]

So my bilge pump ran dry and seized. So I have a replacement but when I wired it in it won’t turn on. Nada nothing. I have power to the pump, the pump works when connected direct to a battery, but just won’t work off the wiring. Help I am going mad!!

 

[billskip]

Float switch?

 

[mcanderson]

No it isn’t working on manual and the continuity through the float switch is fine.

 

[petem]

Does the voltage drop when you connect the pump and try and run it?

 

[billskip]

Does the voltage drop when you connect the pump and try and run it?

Yes,continuity test with a meter sometimes does not indicate the circuit will allow higher amps.

 

[mcanderson]

Let me check that!

 

[mcanderson]

Okay, voltage drops to zero (0) once connected. Remove the pump and back to normal 12+ volts

 

[petem]

Check the wiring at the power supply end (float switch, battery connections, dashboard switch, earth, fuse, etc).

 

[mcanderson]

Dash shows good voltage with the pump disconnected.

 

[gery w]

Measure the voltage at the pump with it connected and switched on, my guess is the voltage measured will be significantly less than 12v.
If this is the case you have a high resistance contact somewhere, probably the switch.

 

[Seastoke]

Yes leave the pump connected and start at the beginning ie fuse is voltage good then switch etc , do not go diving in and pulling things to bits , do it logically. Good luck

 

[mcanderson]

Sorry, I might not of been clear. With the pump connected and the rocker switch set to manual the voltage at the pump drops from 12 to 0. Any starters on how to test the switch?

 

[billskip]

Sorry, I might not of been clear. With the pump connected and the rocker switch set to manual the voltage at the pump drops from 12 to 0. Any starters on how to test the switch?

Bypass it?

 

[Seastoke]

Sorry, I might not of been clear. With the pump connected and the rocker switch set to manual the voltage at the pump drops from 12 to 0. Any starters on how to test the switch?

is there voltage to the switch both sides if so it’s further on but remember you might be losing the negative not the positive , so if testing at switch try and use the neg from the pump.

 

[Seastoke]

As an extra thought , if the manual switch and the float don’t work it has to be the negative as they both would not fail together.

 

[Portofino]

So my bilge pump ran dry and seized. So I have a replacement but when I wired it in it won’t turn on. Nada nothing. I have power to the pump, the pump works when connected direct to a battery, but just won’t work off the wiring. Help I am going mad!!

Why did it keep running to destroy itself ?
Why didn’t it switch off and save itself ?

 

[mcanderson]

How would I know? I wasn’t in the boat at the time. I am surmising that is what happened as a boat neighbour said he heard the pump running he thinks during one of my many absences.

 

[Seastoke]

Have you

How would I know? I wasn’t in the boat at the time. I am surmising that is what happened as a boat neighbour said he heard the pump running he thinks during one of my many absences.

found it.

 

[Portofino]

How would I know? I wasn’t in the boat at the time. I am surmising that is what happened as a boat neighbour said he heard the pump running he thinks during one of my many absences.

General investigation and diagnostic analysis, because the reason i reckon may be related to the predicament you are in now = a switching problem …..from the info gleaned thus far from my arm chair .

I would want NOW to know get behind what killed the other , when the new is wired in doesn’t work .

As you infer if the replacement was a plug n play ( which it isn’t you tell us ) then why waist neurones knowing .I get that .
But you are in a different place .

I mean from my arm chair if the dash switch was on auto and the pump turned on , then has extended running , the heat the amps draw fused the switch plates inside , knackered it ? So it jammed on ? = killed the original pump .
Hence the new pumps not behaving itself when given commands from said switch ……that kinda thing .If so = new switch and or wiring of sufficient grade to cope ?

 

[billskip]

Why did it keep running to destroy itself ?
Why didn’t it switch off and save itself ?

Float switch?