Half scale on the temperature gauge is normal on most vehicles, but if you recognize that as higher than normal on yours, that is not the fault of the sensor. It is just reporting the temperature it sees. To go up when standing still in traffic can be caused by a worn radiator fan clutch. Stop the engine, then try to turn the fan by hand. When it's hot, it should turn with quite a bit of resistance.
The temperature sensor(s) are usually on or near the thermostat housing. There used to be two of them, a single-wire sensor for the dash gauge, and a two-wire sensor for the Engine Computer. Some manufacturers have dropped the single-wire sensor because the instrument cluster is now a relatively unreliable and very complicated computer module, and it gets it information to run the gauges from the other computers. Both of those sensors have an extremely low failure rate because they each only have one simple component inside. Almost all failures in that circuit consist of corroded or stretched terminals in the connectors. A failure in the two-wire circuit will be detected by the Engine Computer which will set a diagnostic fault code and turn on the Check Engine light.
Tuesday, January 7th, 2014 AT 12:21 AM