Bilge wiring question 2 sets of wires BLk & BlK Blk & Brown

JohnEGraham

Active Member
Aug 5, 2008
1,013
Long Island, NY.
Boat Info
250 Sundancer 1998 5.7.
Engines
350 Merc / Bravo 3
Hi, Re-wiring and replacing the bilge pump/float on my 98 Sundancer.
I have schematics but the colors are different
I have a set of blacks together and a black and single brown together coming from the rear of the boat under the engine ( No reds to be found.)
1) i found the hot all the time and its black which is confusing,
Any reason why the black should be hot ( meter from black to negative post an I get 14 volts )
I have been using the attached diagram but not working
Thanks
bilge pump image.jpg
 
No., the pump has 2 wire and the float switch has 2 wire

You should not be hot at any black wire

The schematic is correct either the dash switch or the float switch will turn on the pump!
 
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You should not be hot at any black wire

The schematic is correct either the dash switch or the float switch will turn on the pump!
Depends on where the float switch wires were cut. My switches have two pretty long factory connecting wires coming out of them. Both those wires are black as built by the manufacturer.
 
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"Typically", the pump's wiring would be (1) brown and (1) black. As far as I know, that's industry standard. But depending on who made up the wiring harness after the pump, that could change, of course. Same for the float - wire color could change after the original wiring ends. However, both of float's wires are typically the same color. Usually they are (2) greys - but I've even seen (2) reds (although that's rare). I wouldn't doubt that some switch out there has other colors, too. Doesn't really matter, though since it's just a simple switch and it makes no difference which way current flows through it. But, if your float's wires are black, then you would, indeed, have +12V on one of them... both when the float is tripped.

At this point, it's really doesn't matter. What you have is what you have. Identify which wire goes where and get 'er done. It's easy enough to see the pump and the switch in your boat - even if you had to use your phone to see better - but it should be pretty easy as compared to some boats.

And, no, you shouldn't expect to find any red hot leads (other than that rare case). MOST of the hot leads in your boat, as far as sub-systems are concerned, are NOT red. Otherwise, it would get VERY confusing trying to trace wires.
 
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Although many circuits, like the bilge pump, have standardized colors, theres no guarantee thats what you will find all the way from the switch to the pump/float.

A simple float switch will not have polarity. So it would be easy to see the black wired to the battery and the brown connected to ground. Makes no difference to the float. It closes, voltage passes through to the pump.

The pump on the other hand, has polarity in order to work correctly. So the brown has to be the switched or constant B+ and the BLK has to the B-.
 
Thanks all, 1/2 way there: I switched out the two-position float switch, because it had the electronic tested ( two-finger tested but it did seem to be working and was closed / circuit all the time...
The New float switch is a 3 wire "Water Witch" and the float action is working fine. Pump runs as needed... so at least the boat won't get flooded.
But now I am trying to get the helm switch to work...
BTW the helm switch is a two-position switch ( on -off) type but the "Water witch" diagram shows a three-way switch?... I did find the black from the helm switch at the pump location goes from open to ground... ( but the diagrams are showing sending a positive voltage to the read...
Also, the Diagram shows a three-way helm switch.. now did I just complicate things? I found these two diagrams. I am wired like the bottom one without the 2-way helm switch

water watch w 3 way bilge pump  diagram.png
water witch image.jpg
 
Just wire the water witch constant B+ to the battery, like the old float was. and the bilge will be automatic 24/7, regardless of the helm switch.

With the 3 position switch; OFF/ON/AUTO mode, you would have to remember to keep it in AUTO.
 
Thanks all, 1/2 way there: I switched out the two-position float switch, because it had the electronic tested ( two-finger tested but it did seem to be working and was closed / circuit all the time...
The New float switch is a 3 wire "Water Witch" and the float action is working fine. Pump runs as needed... so at least the boat won't get flooded.
But now I am trying to get the helm switch to work...
BTW the helm switch is a two-position switch ( on -off) type but the "Water witch" diagram shows a three-way switch?... I did find the black from the helm switch at the pump location goes from open to ground... ( but the diagrams are showing sending a positive voltage to the read...
Also, the Diagram shows a three-way helm switch.. now did I just complicate things? I found these two diagrams. I am wired like the bottom one without the 2-way helm switch
Your wording, above, is a little hard to understand (proofread?). But I think what you're asking is how to get the pump to turn on via the dash switch? And, it sounds like you have found the 12V+ wire from the dash switch? Just connect that to the brown pump wire.

I think you're making this harder than it has to be. The pump's + supply wire (typically brown at the pump) needs 12V+. It doesn't care where it comes from - the float switch or the dash switch. Feed the pump with a + supply from BOTH the float and the dash.
 
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sorry for the confusion...
The dash switch does not feed back 12 volts. it grounds out a black wire at the pump location. Switch off equals = open Switch on =Ground
 
The dash switch does not feed back 12 volts. it grounds out a black wire at the pump location. Switch off equals = open Switch on =Ground
None of your posted diagrams reflect this, for a reason. This is not advised, as it requires a constant 12V to the pump at all times. As rare as it may be, if the switched GND shorted to ground post-switch, the pump would run until the battery goes dead.

The pump's black GND needs to the grounded. The brown needs to be switched 12V+
 
Unless you are the original owner, it looks to me like someone wired the bilge switch at the dash to switch ground instead of +12. When you tried to hook it up right, nothing happened at the helm switch, but the float switch/water witch worked ok. Move the other side of the dash switch from ground to +12v and you should be ok.
 
For a standard float switch -
Black to the pump black - this is the battery negative.
Brown with red stripe to one of the float switch wires - this is the battery un-switched positive.
There should be two brown wires - they both tie together and tie to the other float switch wire and tie to the pump brown (positive) wire (all four wires tie together). One brown wire is from the helm switch and the other brown wire goes to the SR Monitor.
The helm switch is fed battery positive from a separate source but same battery bank.

Float switch comes on pump runs, SR Monitor indicates pump running, and helm switch lamp turns on.
Helm Switch turn on, pump runs, SR Monitors indicates pump running, and helm switch lamp turns on.
 
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For a standard float switch -
Black to the pump black - this is the battery negative.
Brown with red stripe to one of the float switch wires - this is the battery un-switched positive.
There should be two brown wires - they both tie together and tie to the other float switch wire and tie to the pump brown (positive) wire (all four wires tie together). One brown wire is from the helm switch and the other brown wire goes to the SR Monitor.
The helm switch is fed battery positive from a separate source but same battery bank.

Float switch comes on pump runs, SR Monitor indicates pump running, and helm switch lamp turns on.
Helm Switch turn on, pump runs, SR Monitors indicates pump running, and helm switch lamp turns on.

Wow,... Thanks, You actually describe the exact color of the wires.
Now, if you know? how do I use a Non-standard float switch with three wires (has a red) Water watch..
water watch w 3 way bilge pump  diagram.png
 
Wow,... Thanks, You actually describe the exact color of the wires.
Now, if you know? how do I use a Non-standard float switch with three wires (has a red) Water watch.. View attachment 77215
Water Witch Red ties to Brown with Red stripe
Water Witch Tan ties to Brown (helm Switch), Brown (SR Monitor), and Pump Brown (all four tie together).
Water Witch Black ties to Black (Bat Neg) and pump Black (three tied together).

Disregard the "Off-On-Auto" switch in the diagram.
 
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