Bilge Pump always running

[Thundar]

Hi Everyone,
What a great resource! I was hoping someone could help me with this.

I purchased a 99 Supra Legacy with low hours that is in great shape. However, one of the issues the previous owner warned me about was that the battery would drain if you ever leave the master switch on (the push-button one directly under the ignition key) and he could never figure out why. As I was cleaning out the boat, I heard a humming noise. Low and behold, it turns out that the bilge will run constantly with the bilge switch off unless you disengage the master switch.

I assumed that it was the float switch that was stuck on "ON" and replaced the pump cartridge. Well, that's not it. It still says on. However, if I turn the bilge panel switch to "ON", the pump goes from low to high. Also, if I manually lift the float switch, the pump goes from low to high.

Here is my question, is the bilge pump supposed to stay on in low mode the whole time unless the master switch is turned off?

[ScottnAz]

Quick answer, no. It will also burn out the bilge pump to constantly run.
My guess would be that your switch isn't wired correctly and your getting stray current constantly powering the switch. Pull the switch and let us know what type of switch it is, and how it's wired.

[Thundar]

I'll check that switch in the panel. It does sound like some kind of short or wiring issue. When I replaced the bilge, the old unit was warm just from the little time I turned the master switch on. It wasn't making any noise, so it was likely burned out already.

Thanks for the quick response.

[jmpotter]

The bilge pump wiring-

Black - ground (duh)
Brown w/ white stripe - Auto (I assume to mean for the float switch)
Brown - Manual (probably for constant running)

The way mine is setup, which I hope is the correct way by the factory, is that is always running when the main breaker is on, but when the main breaker is off, it only runs when the float switch is up.

[Thundar]

The bilge pump wiring-

Black - ground (duh)
Brown w/ white stripe - Auto (I assume to mean for the float switch)
Brown - Manual (probably for constant running)

The way mine is setup, which I hope is the correct way by the factory, is that is always running when the main breaker is on, but when the main breaker is off, it only runs when the float switch is up.

It sounds like yours is same as mine then ... and possibly done on purpose. But I think it's ridiculous. If someone forgets to turn off the master, you'll have a dead battery every time ... which is what the previous owner complained of. I've had plenty of other boats, but never a Supra before. Is this just a '99 model featrue? Surely there is a way to disable this.

[Matt Laird]

I would try to unhook the float switch to see if that the case, If the float is hung up maybe thats whats keepin it on all the time... If you had to you could manuly turn it on every so often...

[Thundar]

I would try to unhook the float switch to see if that the case, If the float is hung up maybe thats whats keepin it on all the time... If you had to you could manuly turn it on every so often...

It's definitely not the float switch. That works correctly.

This thing is either of two possibilities:
A. Intentionally designed this way to expel any excess water from wet skiers and equipment getting in the boat.
B. There is an incorrectly wired connection somewhere causing it to stay on.

I doubt it is a short because the connection would be more intermittent if it was.

[bryan632]

If you have a multimeter, disconnect the wire from your pump and shoot for continuity from the bilge main switch to the engine block. You should get an open circuit. if you are getting less than 1 meg-ohm, then you have a short and are drawing power from another system. you probably want to disconnect your negative battery terminal for this also so you don't read backwards or screw up your multimeter if it doesn't have safety circuits built in.

This is a long shot, but has someone installed a new stereo? that is something that people will usually install pretty haphazardly. if they are using the bilge power for the radio (upstream of the main switch) and done things wrong, it could be putting a small amount of current around the switch. you may also want to check behind your dash, it could be something as simple as two handshake connectors (or whatever you like to call them) touching each other and letting current pass to your pump.

Hope this helps some

[tg0824SSVGG]

This is basically how I have always had them hooked up -- but I haven't always had the 3-way switch - that wire has often just been hooked to the battery directly (no switches) - so that if there is a lot of rain, I want it working thru the float switch.

http://www.boatus.com/boattech/casey/14.htm

[Thundar]

PROBLEM SOLVED!

Matt Laird, you were on the right track. It did turn out to be the float switch but it wasn't that it was hung up. The pump would be running constantly at a low level but when you lifted the float, it would kick in to a higher level.

On my Mayfair Marine Bilge setup, the pump cartridge is separate from the float switch. When I disconnected the float switch, the pump stopped running and the light behind the dashboard toggle switch went off. This obviously meant that the float switch (while technically still working) must have had a compromised seal in the electromagnetic activation switch. It was letting a low current pass through and run the pump at a low rpm. Probably from corrosion.

Fortunately, the part is only $16 and on it's way to me.

Thanks for all the suggestions.

To jmpotter,
If your pump always runs, you may have the same problem as mine and need to replace your float switch.