Why does my bilge pump have 3 wires?

I have been trying to figure out why my bilge pump has 3 wires going into it. I know it uses a internal float switch and is turned on by a switch up front. I need to change it out and I really dont want to use the float system, I just want to turn it on by a switch.

Re: Why does my bilge pump have 3 wires?

+12V
Switched +12v
Ground

Why don't you want to use the float switch...not that you have a choice with this model?

Re: Why does my bilge pump have 3 wires?

No reason not to use both. Just hook up a switch to the one wire(Switched) and the other goes straight to the battery..Should be close to the battery anyway...Remember to fuse it...

Re: Why does my bilge pump have 3 wires?

One wire is a hot wire, one wire goes through the float and is hot only when activated by the float, one wire is the ground.

If you really don't want an automatic pump (thousands upon thousands of boats don't), buy a replacement with only two wires and wire it conventionally through your switch. d

Re: Why does my bilge pump have 3 wires?

The two switches (float & manual) are wired in parallel. They are independent of one another. It is an OR logic. If the water level gets too high, the float switch will activate the pump OR you could turn the manual switch. The advantage of having a float switch is that it monitors the water level in the bilge for you and take corrective action when need to.

You may be thinking that the two switches are wired in series. In this case, it is an AND logic. The float AND the manual switch must be ON to activate the pump which explains the reason why you want to eliminate one.

DO NOT bypass the float switch. It's your "last line of defense".

Re: Why does my bilge pump have 3 wires?

This might be easier to understand. Those are your three wires. If you don't want the float switch, just insulate it or tie it to the +12V switched connection.

Re: Why does my bilge pump have 3 wires?

I like the man with the gate logic.

Re: Why does my bilge pump have 3 wires?

3 wire unit can also be wired to a switch with a center off.
UP is manual center is off and down is auto. Auto put 12 volts to the float switch and if it gets water inside will turn the pump on and pump it out then shut off.