Perkins 6.354 - What sensor is this?

[TheLake]

So am working to identify the sensors on my Perkins 6.354.

I believe #1 is the Water Temp Sensor
I believe #2 is the RPM sender
I believe # 4 is the Stop relay

I haven't been able to figure out what #3 is.

Any ideas?

Thanks,

Chris

 

[High Wire]

#3 is tapped into the coolant circuit. My 6.354 does not have that one. It could be some kind of coolant heater element or high temperature alarm switch. You might want to measure between each terminal for resistance
The others are correct.

 

[TheLake]

That might make sense. Besides the gauges, I have a panel with 3 warning lights (Water Temp, Engine Oil Temp, and Engine Oil Pressure).

I am thinking that if 1 is the water temp sender, then 3 might be for the Water Temp warning light.

 

[High Wire]

That might make sense. Besides the gauges, I have a panel with 3 warning lights (Water Temp, Engine Oil Temp, and Engine Oil Pressure).

I am thinking that if 1 is the water temp sender, then 3 might be for the Water Temp warning light.

The variable resistance sender is for the gauge. Something like 33 to 300 ohms range. I believe that is your #1.
The switch is for the alarm light. That should be <1 ohm when closed or infinite ohms when open.