That part from autozone isn't the same configuration as yours was stock. The stock one had the plug right on it. The '96 & '97 gauge sensor looks like that and is located in the driver side cylinder head with the PCM sensor located near the t-stat.

Here is the wiring diagram specific to your truck:


And here's a view showing the routing:


And it is quite curious that your dash gauge works... The gauge uses the same sender as the PCM in the 98+ trucks.

 

I have looked at my other vehicles, And my 1998 Bravada is the only one set-up without a wire going to the Sensor. It is like a dummy plug in the head kinda looks like sensor but not. Never thought much about it until now with all the op's Questions. Always worked fine temp guage that is.

Maybe OP is looking for a GHOST wire? T.J.

 

thats what I thought because alot of 97s and 99s only had one but we looked at 3 98s and they all had it. also even though the guage works its throwing a dealer code for cooling system malfunction (not sure what the code is because I dont have the paper with me right now but thats the only code it throws)

 

Let us know what the specific code is.

 

the code is P0115 (engine coolant temperature circuit fault)