Bilge Pump Wire

[AKBASSKING]

OK you sparkies,

I am replacing the forward bilge pump in my 86 300DB. This area is just forward of the battery compartment. The shower also drains into this area.

The old pump has three wires: Black, Brown and Brown/White.

The new pump only has two wires, brown and black. The brown wire goes hot (+12VDC) when a switch is thrown in the bathroom.

Have no idea what the brown/white wire is for, unless it is hooked up to one of the engine bay pumps and when they activate it activates this one. This could cause this pump to run dry which could burn it up right? What is the third wire?

 

[TimC]

Isn't there a switch at the helm as well?

 

[tollycraft]

The third is for the pump to automatically bildge when the float swich calls for it to do so.

 

[boatmailster]

OK you sparkies,

I am replacing the forward bilge pump in my 86 300DB. This area is just forward of the battery compartment. The shower also drains into this area.

The old pump has three wires: Black, Brown and Brown/White.

The new pump only has two wires, brown and black. The brown wire goes hot (+12VDC) when a switch is thrown in the bathroom.

Have no idea what the brown/white wire is for, unless it is hooked up to one of the engine bay pumps and when they activate it activates this one. This could cause this pump to run dry which could burn it up right? What is the third wire?

You may investigate a little more. Some older boats had a "return" wire to turn on indicator light on dash while pump was running. Those models usually had indicators for every bilge pump - front, mid, aft or had a "ship" shaped LED indicator panel

 

[AKBASSKING]

The brown/white wire is on the boat side not the pump side. The pump I bought only has two wires.

My deduction at this point is that it is connected to a float that goes to another pump in the engine room....I think. Some more investigation is in order here and I will let you know what the solution is.

Thanks

 

[boatmailster]

those pumps were never connected together!
possible scenarios:
brown wire - override switch in head, brown/white - float switch - should be always on -when battery switch is on, black - negative

brown wire- switch in head connected via float switch or you can burn pump when run dry too long,brown/white - indicator light wire to test that turn on switch in head and touch both wires together, if any indicator light comes on on dash you'll know that this is indicator wire), black - negative

 

[eskimo]

Boatmailster is right. Your old pump has an internal float switch. Replace the new one you bought with one with internal float switch.
Brown +12V from override switch
Brown/White constant 12V
Black to Negative.

Fred.

 

[AKBASSKING]

Thanks.

That makes sense.