2007 Marlin Front Bilge Pump

[Meanwhile]

Anyone else hate wiring bilge pumps? I admit it, I'm challenged by the wiring. The rear bilge pump works automatically or by the dash switch.

My front pump works only by the dash switch. I put a 1500 pump in today as the 500 model was having issues. I cannot figure out the wiring.

Anyone know what the capped off wires are for? They are labeled "A" and "B."

The wiring comes from quick attachments, two for the pump and two for the float switch. Now as the float switch was wired it is obvious the intention was for an automatic function.

Any help on others wiring for the front bikge pump woyld be helpful.

Not helpful at all but I used a 1500 pump I had on the shelf, it is an automatic/manual pump with three wires. Now I'm very confused.

Randy

 

[seasick]

In order for the pump to operate both manually and automatically, there should be three wires powering the pump. One is ground of course. The second is a switched 12v feed fed form the switch panel. That is the manual mode. The third wire is constant 12v and that is wired through the float switch. That feed may be also wired to the battery switch and not directly to a battery but normally is wired directly to a battery
If the connector you show is the main connection, it only has two wires. So unless you find the third wire (constant 12v) you will not be able to wire an automatic setup. Is it possible that those two wires are the constant and switch 12v and that there is another ground connection somewhere?. A voltmeter may help identify what the wires are.

 

[kirk a]

I googled marine wiring colors, and the two things I found for white/red wire were trim tab power, or an indicator for a Mercury thunderbolt ignition, neither of which make sense for a wire in the forward bilge.

I'd probably just buy a manual pump and install it with the same two wires. If you have a float switch already, it is probably the easiest solution.

 

[DennisG01]

You can look at your wiring diagrams (Grady manual) and can likely find out what those two capped-off, white w/red wires are. But at this point, I wouldn't worry about it since it doesn't affect what you are doing. It is probably for some option your boat doesn't have. Or possibly your model shares a wiring harness with another model that uses it.

The normal colors used for AUTO bilge pumps are black, brown and brown w/white (or tan). All brown is typically the "auto" lead... meaning it's always hot and connected to the battery. For a non-auto pump, black and brown are the colors. This is what the pump manufacturer usually uses - a boat builder sometimes takes some liberties. But looking at your picture, and since you said the pump only operates off the dash switch... I'm going to assume that the side of the connector that has the brown and black wire is the pump's wires. And the black and black w/brown wires are the boat's wires, with the black w/brown being your switched, hot lead. You can either cut before or after the plug, but I would leave the plug in place. With that in mind, connect that brown wire to your pump's brown w/white. Now the switch should operate the 'new' pump. If you want, hook the lead coming from your switch to the new pump's brown wire... this would turn your pump into a 'sort-of' auto pump... meaning, the switch would activate power to the pump but the pump won't turn on until there is enough water in the bilge. Most likely, though, when you turn your battery switch off, you would lose power to the dash switch... so you couldn't just leave the dash switch 'on' all the time... unless you supply an always hot lead to the switch.

 

[Meanwhile]

Thanks for the replies. DennisG01 has identified the 3 wires coming off the new pump. I tried attaching power to the auto wire and it did test with the push button. Doing that does not power the switch.

I gave up, hoping the rear bilge and high water alarm is enough to alert me. The front bilge is nice to remove rain water. Next winter the boat will be in my new shop, nice and dry.

 

[seasick]

If the pump has a built in float switch or sensor, then it would have three wires but if it uses a separate float switch, it only needs two wires. You do need three wires from the harness to the bilge area. if auto mode is to work, you need a ground and one wire that has 12 volts present all the time regardless of the manual switch on the switch panel. If you want manual mode, you need another wire that has 12volts to ground when you flip the switch on the switch panel

I read you original message and now I think I understand. Your bilge connects to two connectors. I suspect that one supplies the constant 12 volts and the other, the switched 12 volts. The power leads should be brown, maybe with a color stripe (black on some models). You need to test those wires for juice using a test lamp or voltmeter.
If you do find the two power wires, it is a simple job to wire the pump but I need to know if your pump has a builtin float switch or a separate one.
If separate, the constants voltage wire connects to one lead of the switch and the other lead connects to the hot (probably red) wire on the pump. Connect the ground to the black wire. Lifting the float switch should nor start the pump.

Now run a wire from the switched power wire in the harness past the float switch and connect it also to the same red pump wire that the float switch connected to) Now the pump should run when you flip the manual pump switch on the panel.
Note that the constant 12 volt wire runs back to the battery or the hot side of the battery switch. It has by code an inline fuse. Find that fuse and make sure it is good. The aft bilge also has a similar connection with a fuse and is probably connected to a different battery. Point is that you have to try and find the correct fuse for the mid bilge.

 

[DennisG01]

Thanks for the replies. DennisG01 has identified the 3 wires coming off the new pump. I tried attaching power to the auto wire and it did test with the push button. Doing that does not power the switch.

Bail, I'm confused. It's not clear if it is or is not working for you. What push button are you referring to? And "power the swtich"?

If the circuit coming from the dash switch is active (has power) and your new pump is good, then everything should work just fine. If it's not working, maybe you clarify what you've done and what you have checked (power at the connector, for one, with the switch ON).

 

[Meanwhile]

To clarify:
Old pump used 2 wires to it. It used a seperate float switch. The float switch wires were not connected directly to the pump. Both sets of wires disappear into the darkness, unknown what connections are available in the darkness.
New pump uses 3 wires as you described. New pump has a test button (foil patch thing, push here for 5 seconds).
As wired now the panel switch works for manual mode. As wired now the auto wire is not connected.

So I don't know where the grey wires on the old float switch go end up.

I could try to connect the float switch grey wire to the automatic wire on the new pump. Boat is now moored 90 miles away so no more instant trouble shooting. I can get more photos later.

 

[seasick]

Please tell us the make and model of the pump. Three wires leads me to believe it has a built in float switch. In that case you existing float switch is not needed but to get the new pump working, you need to find out where the connection of the old float switch is. One of its two leads is the constant 12V.
If you measure voltage at the two wires that connected the old pump, there should be juice when you lift the float and when yo lower the float switch and use the manual switch. If that is not the case, you have wiring issues and not necessarily a bad pump.
Did the old arrangement ever work correctly?

 

[DennisG01]

I think I may be saying the same thing as Seasick, but...

"The float switch wires were not connected directly to the pump"

In regards to the old/existing float switch wires... One of them will be a constant hot and the other is a ground. Using a voltmeter, check to see which one is the +12V. Some meters will show reverse polarity... if not, connect your meter's negative lead to ANY ground you can get a hold of and then use your positive lead to each of those old/existing float switch wires to see which one is +12V. Use THAT wire to your new pump's BROWN lead. The other wire... coil it up high and put some tape around the end - you won't need it. Now your pump should work manually via the dash (as it does now) and it will also work automatically.

 

[seasick]

Found this very interesting article.
https://newwiremarine.com/how-to/wire-bilge-pump-switch/

 

[MA208]

As luck would have it mine just failed. Attwood didn’t make the same model so here’s what the marina put in.