How to test thermostat sensors?

[OllieVR6 0]

I found a thread briefly explaining how you test these but I'm useless with a multimeter.

 

I put the multimeter on ohms (not sure if it matters which one) and got a reading for my black sensor but my blue sensor doesn't give a reading and of the four pins on the yellow sensor I only get a reading on two pins not the other two.

 

Also my blue sensor is black (the sensor not the plug) with a blue ring on it, is that correct?

 

Any help would be appreciated, thanks.

 

Sent from my HTC One X

[robo22sri 10]

I don't know how to test them but I bought all new seeing as I pulled it all apart

 

I paid £50 for sensors from AVS spares

 

I bought a new blue and yellow and also rad fan switch

[Wullie 1]

There are loads of tutorials on You Tube on how to use a multimeter. I found them really helpful and turned my multimeterfrom a pretty ornament into something useful

[OllieVR6 0]

Well I have the blue sender in front of me. With my multimeter set to ohms (20k) I get no reading at all from it. Dead?

 

I do get a reading across 2 pins from my yellow sensor but not the other 2, is this also dead?

[RW1 0]

Blue sender spot readings:

 

15'C - 3,000 ohms approx.

50'C - 1,000 ohms approx.

70'C - 425 ohms approx.

90'C - 250 ohms approx.

 

So its goosed.

 

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Yellow sensder:

 

Across pins 2 & 3 I'd expect some readings similar to the Blue sender above.

 

Across pins 1 & 4 is the "Run-on" fan switch. This closes at 101'C - 107'C to make circuit.

 

So the switch is more difficult to test as a pan of boiling won't trigger it. The only way would be to use a Pressure Cooker pan so that you can raise the boiling water up above 100'C. Alternatively, try and use the engine hot.

 

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