Oil pressure sender unit

Ive got a leaking engine oil pressure sender unit on a Perkins V8 which I need to change out, it has three wires. I have another one that look just like the problem one sitting in my workshop with two wires. Any thoughts on if this woulld work and if so how would I connect it up?
Bill

I don't know. What machine is this on? Where was it made? Do you have a wiring diagram? I think all of my oil pressure sending units have one wire. The ones that have multiple wires are warning and/or shut-down systems.

There are 2 types of sending units.

A dry contact type that can have a number of configurations, most common is normally closed to ground, the type that would activate a low pressure warning light (1 terminal). An other configuration can be a common/normally closed/normally open contact (3 terminal). That may be what the leaking one is. The new one could be normally closed, or normally open (2 terminal). There are many other combinations, the only way to know is ohm it out, or look it up by part number.

Then the other type is a variable resistor. It is used for an electric pressure gauge.

If all 3 terminals are in use on your leaky one, it would be difficult to make the 2 terminal one work. It could probably be done with the addition of a relay, but would be more trouble than it's worth.

Any way to find a wiring diagram?

Or you can trace down where each wire goes, what it does, ohm out the senders, see what configuration each has...

Or buy the correct sender.

I would give getting the right one my best try. Otherwise you will probably have to give up a portion of the safe guard system, could even cause a battery drain, lots of possible undesirable consequences.

That's a more than you need to know reply Who'da tunk a OP sender could get so complicated... I wonder what the 3rd wire is for my first thought its for another light are something to do with the charging system...

Curiosity has got me I may have to drag my NAPA illustrated catalog and bone up on it...

This one is set at 10 psi. Is is somewhat adjustable, but there are other ranges available. Will direct replace what is on your tractor.
clicky

Need to know whether you have 12 or 6 instrument panel lights and a left or right side exhaust. They all have a 3 wires but different colors/connections.