coolant temperature sensor

[pontiacgp]

Hi guys !
I come back here because I received the TS66 temp sensor, I put it in place of the previous temp sensor and the gauge still doesn't work.
I don't understand :
- if I disconnect the connective wire the temp gauge shows 0
- if I put the connective wire to the ground the gauge shows maximum
- with the previous temp sensor, the needle moved a little bit if the engine was really hot (stuck in traffic after a long drive), but not enough.
- with the new temp sensor, the needle doesn't seem to move at all (but the weather is colder than usual today)

So I guess the wiring and the gauge work well...

I only see 2 possibilities :
- the temp sensor ts66 I just received doesn't work
- my engine doesn't become enough hot ? (but I can't let my hand on the radiator)

What do you think ? What could I do ?

With the sender installed use a multi meter and check for continuity from the body of the sender to the block of the engine. If you have continuity start the engine, put the multi meter on ohms and check to see if the ohms decrease as the engine heats up.

If you have no continuity between the body of the sender and block remove the sender and clean the threads. I'm not sure if your used any thread sealant but you are not supposed to use any sealant cause that can interfere with the ground that the sender requires.

If you don't have a multi meter you can check the body of the sender for ground by grounding the wire to the base of the sender and your gauge should go to hot

 

[mickeypowa]

Hi guys !!
Thanks for your answer !!
So, for the new I've check with a multimeter between the body of the sensor and the ground and I get 0 ohms, so the body of the sensor is grounded.
I used a little teflon tape on the thread like it's written on the Haynes book, but it seems OK as the body of the sensor is grounded.
Then when I test between the pin of the sensor and the body of the sensor ( or ground ), I get 1, unlimited resistance, and it doesn't change if the engine is hot...

So the sensor doesn't work.. it's strange...
With the previous sensor, the resistance was dropping while the temperature was going hot, but not enough to put the needle of the gauge in the right place...
I will put back the previous sensor tomorrow, to make a resistance test with the same protocol...

Do you think it's posible that a brand new sensor doesn't work at all ?!
thanks
Mickeypowa

 

[pontiacgp]

you can test the new sender by removing it and putting it in a pot of boiling water. I am not sure what the ohm reading should be for that sender at the 212° but it should be well below than what it was at room tempature

 

[mickeypowa]

Hi guys!
I put back the previous temperature sensor and I did again the test.
When the engine is cold I get 2500 ohms and when it's hot I get 400 ohms. But the needle of the temp gauge only move a little bit.
I think my new temp sensor is not working at all as it has unlimited resistance regardless of the temp.
I guess I would need a temp sensor droping to maybe 100 ohms when it's hot to have a proper value on the gauge..
maybe I will try to hook a 100 ohms resistor to ground and to the connecting wire of the sensor to see what value shows the gauge ?
I've seen on rockauto, there is the TS76 which is compatible with my car with 3/8" thread. Does someone knows what is the difference between the ts-66 and the ts-76 ?

Thanks,
Mickeypowa