Originally Posted by Unicorn Dreams
Rule pumps usually have 3 wires
ground wire- black
hot wire, red
auto on wire, other wire
When wired up, the hor and ground wire is hooked up at all times,
The 3rd wire go to the float switch, UNLESS. . . .
Huh? the ground wire is connected to boat's DC ground.
- - The red "hot" wire is attached to one outer terminal of a SPDT switch with the boat's DC supply wire attached to the center (common) terminal and the so you can manually turn the bilge pump on or off.
- - Additionally, the grey or automatic wire (on bilge pumps with an internal float switch) is attached to the other outer terminal of the SPDT switch.
- - Then you can flip the switch to turn the pump on manually or flip the switch to the other position to "arm" the automatic function.
- - If you have an external float switch then the pump will only have two wires, ground and hot. One of the external float switch leads is attached to the bilge pump "hot" (red) wire. The other external float switch wire is attached to the SPDT switch as described above for the automatic function.
- - The colors of the wires on the pump may vary so you need to read the instructions that came with the pump to be sure which wire does what.