Temperature and Oil Pressure Senders
Do I need a Sender or a Switch?
Senders attach to Gauges and read a percentage of ground to make the gauge read the correct value. The OHMS that this gauge work on are for two applications. Single Station which means it is sending information to one gauge, and dual station which sends information to two gauges like when you have a fly bridge or two places to steer from.
Switches: These are make/break contact senders. Used primarily as alarm senders or fuel pump oil pressure senders. The sender will typically complete a ground when activated. Like if your engine goes over 200°F it will complete a ground to set off an alarm, buzzer or light.
Before ordering please know if you are looking for a Sender for a gauge or alarm. and the thread size of your old unit. Oil pressure is almost always 1/8 NPT. Temperature senders can be 1/8, 1/4, 3/8 and 1/2 NPT.
You can take the wire off of the sender with the ignition key on and ground the wire to the block or base of the sender. Alarm Sender will set off the alarm. Senders will make the gauge peg (go all the way over).
They are not interchangeable.
We hope this sheds some light on the types of senders.