Why does a 96 intake have 2 coolent sensors and like a 01 has only 1 sensor ?

 

That changed in 98 actually. The way the whole instrument cluster worked changed as well. Instead of the cluster getting direct readings from various sensors, the PCM gets the information.... (including engine temp, oil pressure, even FUEL level.....) and then passes it along to the Central Timer Module. (which is basically just a network hub.) The CTM then passes the info to the cluster, and the cluster uses it to decide where to put the various needles, and what lights to turn on.