The idle sensor isn't an on-off kind of thing. Hook a resistance meter to it and while you change the temperature you should see the resistance change. These are not a high failure rate item. The things to watch for are that they shouldn't leak when you reinstall, the wiring connections should be clean and tight, and the wiring going to the sensor should be in good condition, not brittle or pinched. It tells the idle ECU to make the motor idle faster when cold and slower when warmed up. It is wahat is known as a thermistor. The resistance goes down as it gets warmed up opposite to a resistor. David Teitelbaum vin 10757 --- In dmcnews@xxxxxxxxxxxxxxx, id <ionicdesign@xxxx> wrote: > Ok i have one sensor to test and i dont know how so i am asking for help again. Part #102480 Idle Speed Thermister or also known as Constant Idle Switch Thermister. This switch has 2 connection tabs on it. I hooked up a tester and > ran it uneder hot and cold water and it didnt seem to do anything, i was checking to see if it made a contact under hot and cold water like the Lambda sensor does. > > Anyone please help me with this so i can enjoy the summer driving my car. > > I am not electrical smart, i am electricly challenged so i need easy instructions to test this sensor. > > Thanks > Mark > 6683