Wiring of the 3 pin coolant level sensor

[B1ack_Mi16 67]

So a big thanks to Hilgert that managed to get me a black phase2 / diesel expansion tank for my 205 Mi16 project.

 

Anyway, the original loom had a regular expansion tank with the 2 pin level sensor, and I believe that the wire going to the dash is earthed when the coolant level gets too low?

 

So this new one looks more like one from a 405;

http://www.serie04.com/fr/405-refroidissement-moteur-essence-tu/2147-capteur-de-niveau-d-eau-1.html

 

But how it is supposed to work? I see in the 405 Haynes the pin 1 is earth, pin 2 is going to the instrument cluster and pin 3 is getting switched (+) live when ignition is on.

 

I have hooked it up to 12v on pin 3 and earth on pin 1 but not getting any conclusive readings from pin 2 anyway.

Getting about  0.65v between pin 2 and earth. Sensor might be gone as it doesn't look too good.

[ade 4wd 11]

Pin 1 earth

Pin 2 output

Pin 3 12 volts

 

The output goes low when there is no water in expansion tank.

To test, connect a bulb across pins 2 and 3. Put the probes in water and the bulb is off. Take probes out the water and after a few seconds the bulb will be on.

 

[B1ack_Mi16 67]

Ok thanks..

 

So I need to wire in an extra relay  that grounds the wire that goes to the instrument panel then?

[ade 4wd 11]

No relay is needed. The output wire can connect directly to the instrument panel. 

[B1ack_Mi16 67]

Ok, I suppose my sensor is defect at least, as I was not able to get a 1.2w bulb to light up either way I tried to connect it.

But will just wire it up and get a sensor later on.

[Anthony 1,003]

To be honest, most of the later type level sensors I've seen are knackered - so unless you're lucky or you can find a new one, it might all be academic anyway.

[skeggyrik 3]

Can you still get new sensors for the later phase 2 tanks?

Were they common to other models?