i recently bought a 96 lumina with a 3.1 and i have read that there are 2 coolant sensors. i have a sensor under the egr valve on the heads that is not hooked up to anything and was wonder is this is one of them. i laready have checked the fans and they work also have replaced coolant sensor by the thermostat still my temo gage is not working.any sugestions

On the 96, i believe there is only one, and it is undernieth where the throttle cables hook onto the throttle body. Not too difficult to change at all, you dont even need to drain any coolant. Just need a 19mm deep 3/8 drive socket, and a swivel. This is a 3 wire sensor. Two wires controll the PCM (fans) and the green wire controlls the the guage on the dash. It is possable for one to work and the other to not. Its a cheap part, 15 bucks i believe. You may want to start there.