Water pump wiring... what is signal wire used for?

[EugeneR]

I have replaced my water pressure pump. The boat has 3 wires coming to the pump, connecting to 3 wires on the pump. Positive, negative and a signal wire which looks to returns positive when the motor is operating, otherwise negative. My new pump has 2 wires only, and works, but there is no feedback to the boat when the pump is running.

I could tap the connection between the motor and pressure switch to get the same feedback, but am wondering why the boat needs the feedback wire? I am not aware of any indicator that lights up when the pump is running, the noise is enough. I assume Fairline would not have put it there without reason, but what could that be? I am not able to trace the wire.

 

[Bertramdriver]

There may be or have been an run indicator light somewhere on the boat, but if you haven't found it, you probably don't need it. Chill

 

[superheat6k]

The old pump on my Fairline had this connected back to an indicator on the FW pump switch, so it would flicker on when the pump ran. I could have made an extra connection to the pump after the pressure switch, but as I can hear the pump running I thought 'space and waste of ...'