WaterPressure Switch

[JerryLouisMartin]

Does it matter on this switch where the wire goes?

Which one of the two connectors is the WP or Ground?

Does it matter what wire goes where?

[Novus]

That depends on if it is a simple "dry contact" style switch. Dry contacts are just two metal pieces that close when water flows. Chances are that if it's just two wires, it's dry contact and it won't matter.

If it's not dry contact, you likely won't hurt anything by putting it in backwards. It just won't work. And neither should your laser, if memory servers, because the connection between the WP screw and GND on your laser driver is open.