Bilge pump not running off of the battery

[FlyingSailor]

So I’m at a loss, I have an 83 Cat 27 that the bilge pump has worked just fine. It’s connected to a three way switch and connected to a float switch and the battery. Previously it worked just fine with all breakers off connected just to the battery, but now suddenly it’s not working unless the master breaker and dc master switch are turned to on. But directly to the battery, it’s not.

So far I’ve checked all fuses, they look good. And I cleaned all terminals and have reseated them multiple times. I can’t for the life of me figure out why it works with the breakers on but not with them off all of the sudden. The high water alarm still works, so I know the battery isn’t causing issues. Any ideas?

 

[jeepbluetj]

Trace the wiring.

Interestingly it should be either/or - from the panel or direct to the battery. (or downstream direct from the battery, like the 1/2/OFF switch)

 

[kloudie1]

When you note "Master", is that the manual switch? Will the pump run and shut off from the float switch if the master battery disconnect is on and the DC master is on?
The master battery switch is the 1-2-Both .. it should have an "always hot" terminal that is connected to one or the other battery inputs (not both) That terminal is what runs the bilge pump when the main switch is off. If that terminal has no voltage on it when the switch is off, the master switch is bad.

 

[jssailem]

All of what @kloudie1 indicated... Also have you checked the float switch in the bilge.

Wires in the bilge corrode. The junk that finds its way to the bilge, jamb the switch causing a failure. Sometimes it is the simple things.

Otherwise get your DVM out and start checking the wires for power at all of the connections.

 

[markwbird]

Could be a bad float switch or wiring. The float switch is down in the grime and does not last all that long. Same with wiring and connections.

 

[Benny17441]

Your 83 Cat like boats of its era probably came from factory with a manual breaker switch to the bilge pump. It seems some PO along the way added a parallel circuit with a 3 way switch with a float switch hardwired to the batteries. It seems the PO installation may have failed and the culprit is usually the "float switch".