I need some help in locating the BLACK sensor that goes directly to the temperature guage. I was told by an online mechanic that this car has three sensors, Brown, Blue and Black. The black one senses the water and oil I have been told and goes directly to the temp' guage. The reason for changing this is that the temp' guage moves to about one third up on idling for 10 minutes, but goes back down to zero when driving, showing that the engine is cold, but of course it isn't, and there is no overheating at all. Can anyone tell me where this illusive black sensor is! I can't locate it anywhere and it is a listed part for that car. Many thanks, in advance. Tony