Set up a test station on my workbench today. Used a battery charger that delivers either 6V or 12V. Ran the hot to one side of the 100-212 NOS gauge I have, then left the other side of the gauge to the center terminal of the sensor and clamped the negative of the charger on the sensor threads to complete the circuit. Put the sensor in a shallow pan of water and heated the water from underneath. Tried a TS-6 sensor first (which is what you get from the repops). No reading on the gauge until it got to about 195 degrees at the sensor (I used a thermometer to measure the water temp) and then the gauge spiked to 212 degrees. Let it cool down and the gauge moved a bit downward then dropped totally to the other end of the scale. Kinda shows what others have said their experience is with the senders in their trucks. Tried three other sensors and pretty much the same deal. Then switched the voltage to 6v and repeated the process. On 6v power, none of the sensors registed on the gauge no matter how hot it got. I looked at three of the sensors and they are marked 12v. I'm thinking that I'll purchase a 6v sensor (if I can find one) and try that to see how it reacts. If my guru at the factory is correct, a 12v thermistor is calibrated to be accurate at 12v. Therefore, a 6v thermistor should be done the same way. I scored a NOS GMC 100-220 temp gauge yesterday so once I get it, I'll test it as well.
