This low pressure warning switch is perfect for turning on a light (sold separately) to indicate a loss of fuel pressure. The pressure is easily adjustable from 2 to 7 psi. Just remove the rubber plug on the back of the sender and adjust the set screw using a 7/32" Allen wrench (turn clockwise to increase the trigger pressure; counter-clockwise to lower it). Installs in any 1/8 NPT port.
The single-terminal switch is designed to short itself to ground when pressure drops below the set point. It must be used with a 2-wire warning light (not included). If the switch is installed in a rubber fuel hose, a separate connection will be required from the switch body to the chassis ground.
Wiring is simple: Connect a switched power supply (e.g., power out from your ignition switch) to one wire of your warning light. Connect the other wire from your warning light to the terminal on this switch. Add a ground wire from the switch if needed, and you're done! When you turn on the ignition, the switch will turn on the light. When fuel pressure builds, the light will turn off. If the pressure drops, the light will come on again.
Sold individually. Warning light sold separately.