Zetec coolant sensor help please!

[Chris Scott]

So, having started the electrics, here comes the first of many (I suspect) questions!

The engine (Zetec Silvertop) has two sensors, does anyone know which is which - I assume one is gauge and one rad fan switch? 

Also, both have 2 pins but only one wire, so I assume one pin just goes to earth? 
 

Finally, do the sensors have a pos and neg or does it not matter?

Thanks in advance 

[tractor]

there are two sensors fitted to the engine one is for the oem ecu and one is for temp gauge 

[nelmo]

Are you keeping the original inlet manifold or changing to the GBS plenum/TBs? 

On my blacktop, I never reused those sensors as the GBS plenum has a hole for the air temp sensor and the water temp sensor went through my thermostat. Fan is controlled by the ECU. 

But if you do want to use them, I'd imagine polarity is not important - they just work by changing resistance between sensor and ground, I think, so either way is probably fine. 

[Chris Scott]

Thanks, I’ve got the aftermarket coolant rail and bike carbs on a custom inlet.

Ideally I just need the temp gauge one to work as I’m going to have the coolant fan on a switch.