I wondered why the sensor had 3 wires but only used two of them on this engine. I had debated replacing that sensor but noticed it was worth a small fortune. The 2001 sensor was considerably more expensive than a 2003 one though. I ended up grabbing a connector off of a 1994 C1500 and ordered a sensor for the same thing. I had to use a bushing to make it fit. It did fix my temperature gauge though. It reads the same as the scan tool as it warms up now. The wiring is only temporary while I made sure it worked before a permanent fix.