Chrysler Repair: 1995 Chrysler Lebaron Convertible, coolant temperature sensor, chrysler lebaron

Question
I need to know if there is a fan switch, and if there is a sensor to turn the fan on. The fan comes on when you turn on the air conditioner so we know it works but I don't think it is coming on when it should to cool the motor.  Thanks Shirley  

Answer
Hi Shirley
The fan switch is in fact called a relay and it it working because it is called into play by using the AC. The other way the relay is called into play is when the coolant temperature sensor resistance drops to a critical point due to being warmed by the coolant and that prompts the engine controller to ask the relay to turn on the fan. The coolant temp sensor on the 3.0L V-6 is directly next to the thermostat housing manfold which is the hemispherical metal object on the top of the engine with the big upper radiator hose going into a fitting on its side. The sensor is screwed into the engine and has a two-wire connector on its tip. The colors of the wires at the connector are tan/black and black/light blue. If the temperature gauge on the dash indicates that the coolant is nearing 3/4 scale or more then the fan should come on. That is when the engine reaches about 210 degrees. Otherwise the fan won't come on. You could temporarily block off the air intake to the radiator with a piece of cardboard to drive the temperature up and see if the system is working that way. Or disconnect the plug-in connector (lift the tab on the side of the connector) to the temp sensor which should start the fan also. The final test would be to measure the resistance across the two pins of the sensor socket when the engine temp gauge is reading 3/4 scale. It should read around 700 ohms.
If the fan isn't coming on when you think it should, you need to verify that the temp of the coolant is really at the 210F level. If the engine is not really ever warming up that high then the thermostat is opening at too low a temp and should be replaced.
In any case that is how the fan is controlled for cooling purposes. Let me know if you have any questions or what results from your tests.
Roland