Toubleshooting Bilge Pump...

[haydenfox]

And other electrical issues, but my problem is the bilge pumps right now. They weren't working so I replaced the switch and all was good. They stopped working again today. I checked the wiring at the switch and everything looked ok. The previous owner has them wired in a way I don't understand, not that I would anyway. Both pumps had an automatic float switch which he disconnected. The pumps themselves are wired to the switch at the helm, there is no in-line fuse but they are connected to breakers next to the switch.

Im not too inclined but have tools and can follow instructions. I have a multi-meter and a test light. Thanks

 

[sweet addiction]

Re: Toubleshooting Bilge Pump...

I would start by tracing the power back to the battery.

 

[haydenfox]

Re: Toubleshooting Bilge Pump...

I would start by tracing the power back to the battery.

How?

 

[Okieboatguy]

Re: Toubleshooting Bilge Pump...

I have a stupid question. How are the pumps connected to the switch? I have seen people twist to the old set of wires and tape them which causes corrosion and then leads to a bad connection, causing poor current flow and eventually an open (or dead) connection. That being said, you stated you had power at the switch, I would re-test at the switch and work my way back to the pump.
Put your negative (-) lead from your meter on a good spot that is a constant (-) neg from the battery. Remove from the back of the pump switch the wire that runs to the pump. Place the positive lead on side of the switch that is connected to the (+) side that is supplying the constant power and verify that you have the approximate 13.2 vdc. If so then move to the side of the switch that is not connected (the side that normally goes to the pump) and check the voltage there, remember to toggle the switch, it should go from 0 to 13.2 depending on the position of the switch, if it stays 0, then the switch is bad. Now verifying the switch is good and power flows through, re-connect the pump and re-test, if you see the same results, the problem is back towards the pump either an open wire along the way or in the pump. If the voltage drops and the pump does not turn on, then the problem is definitely the pump. If the voltage drops to 0vdc then you have a short somewhere.
Let me know if that helps, if you need more info or more specifics I can help as you get down to the nitty gritty.

 

[haydenfox]

Re: Toubleshooting Bilge Pump...

My battery and switch are way too far apart to use the battery as a ground. Is there a different ground source you can suggest? And can I use a test light? I'll check how he has it wired today, Im sure it's spliced/twisted in there somewhere.

I went out and began tracing the wires this morning, oh boy. Anyhow, the ground wiring looks conventional. He has 4 hot wires connected with a wire nut though. It looks like the wires, 3 brown and one brown w/ orange stripe go to the pumps, aerator and helm switch. The aerator works fine under this system which I didn't completely understand because they are connected but work off different switches.

I also put a test light on it. I got nothing at any point, switch or pump. Aerator lit up. Let me ask, I hooked up the light to ground and stuck point to hot and visa versa, is this the appropriate way to use the tool? Also used a multi-meter touched hot to ground. Got a negative reading from one pump and 1.2 volts from the other. I did not use at the switch.

 

[Okieboatguy]

Re: Toubleshooting Bilge Pump...

You can use any known good constant ground, that would be fine, and a test light will work as well just to make sure you are getting the proper voltage.

 

[haydenfox]

Re: Toubleshooting Bilge Pump...

You can use any known good constant ground, that would be fine, and a test light will work as well just to make sure you are getting the proper voltage.

Any input on the circumstances I outlined above? Thanks

 

[Okieboatguy]

Re: Toubleshooting Bilge Pump...

There should be a ground near the switches. Look for a black wire going to a terminal block, and that would be a good ground to test from.

 

[haydenfox]

Re: Toubleshooting Bilge Pump...

Ok, here's what I accomplished today. Removed pumps and made sure the impeller was spinning. Ran a jumper wire from pumps to battery and both pumps kicked on. Disconnected all the wiring, cleaned and put fresh connectors on. Still nothing.

After cleaning wires and connections I retested with the test light. I connected clip end to positive on the battery and touched the ground connection, it lit up. I reversed the application to test the hot leads and got nothing. Still not getting anything from the switch except ground. Am I testing it right? I did get nearly 12 volts when I tested the switch with the multi-meter.

Im at a loss...

Edit: I just ran a jumper from the switch and got nothing. I don't understand how I can get a volt reading and not be getting power from the switch.

 

[Silvertip]

Re: Toubleshooting Bilge Pump...

Here is a diagram showing current flow through two lights. Follow the arrows to see the flow. You are not using the test light proplerly. Connect the clip to ground. Use as long an extension wire as necessary to reach a KNOWN GOOD GROUND. Now, probe the INPUT to the switch. Power yes or no? Yes = good. Turn swtich on and probe OUTPUT (lo9ad) side of switch. Power yes or no? Yes = good. No = bad switch. Probe positive wire at pump. Power present yes or no. Yes = bad ground. No = broken wire between switch and pump. If there is no power at the line (input) side of the switch either the fuse is bad or the +12 volt connection is interrupted. No "buts" here. Follow the flow of juice. When you lose it you found the problem.

 

[haydenfox]

Re: Toubleshooting Bilge Pump...

Here is a diagram showing current flow through two lights. Follow the arrows to see the flow. You are not using the test light proplerly. Connect the clip to ground. Use as long an extension wire as necessary to reach a KNOWN GOOD GROUND. Now, probe the INPUT to the switch. Power yes or no? Yes = good. Turn swtich on and probe OUTPUT (lo9ad) side of switch. Power yes or no? Yes = good. No = bad switch. Probe positive wire at pump. Power present yes or no. Yes = bad ground. No = broken wire between switch and pump. If there is no power at the line (input) side of the switch either the fuse is bad or the +12 volt connection is interrupted. No "buts" here. Follow the flow of juice. When you lose it you found the problem.

Thanks! That's a big help. I'm using the tach bolt as a ground and that is where all the helm wires are grounded also.

BTW, how do you know which terminal on the switch is load vs. input?

 

[Okieboatguy]

Re: Toubleshooting Bilge Pump...

Thanks Silver, a picture says a thousand words!!!
Hayden, in a older boat it may be hard to tell which is the load, (hot) post. You are going to have to test each one, and toggle the switch. If one side stays hot, that is it. If you verify and the other side and it is hot and then cold, that is good. if both sides stay hot, that is bad.
Slow but sure we will get there.