I've had my 95 XJ for about 2 months. Recently while poking around under the hood and installing a new intake I found the temp sensor taped up and tucked under the fuel rail. There was a real nice plug installed in the water pump housing. I have nothing but idiot lights. My XJ runs pretty good. No overheating issues. What's up with that?

 

No idea on your water pump but the sensor your ECU/PCM uses should be screwed into the thermostat housing. Without it it will think the engine is cold all the time and waste gas. The dash gauge (or idiot light) uses a separate sensor at the rear of the head on your model year.