Chrysler Repair: 95 LeBaron 3.0 L V-6 Radiator Fan wont activate, coolant temp, radiator fan

Question
My Radiator Fan will only run when I turn on the A/C.  I just replaced the Heat Control Module next to the Thermostat, the Thermostat, and a new Fan Motor.  All the parts are correct and the Fan will not turn on when the engine gets hot.  It will just overheat unless I turn on the A/C.  I ran it like this for the past two years and burned up the Fan motor, and that is why I just replaced it again.  Thanks for any information.

Answer
Hi Doug,
The sensor that causes the engine controller to activate the fan relay is the coolant temp sensor which is located next to the thermostat housing on the top front of the engine. It has two wires, black/light blue and tan/black. It is probably not functioning but you can check it: the resistance across its terminals should be 10,000 to 14,000 ohms when the engine is cold, then as it warms up the resistance should move down to between 700 and 1,000 ohms. If not, then replace the sensor.
You should also find a fault code stored in the engine controller memory. Turn the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less. Then watch the check engine light, which remains on, to begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat for accuracy. Then group the counts in pairs to form the two-digit fault codes. If you get a 15 or a 17 that would corroborate my diagnosis. The last code is always 55 which means end of readout. Simply unscrew the old one and put in a new one. If the resistance seems to be ok then you will need to test whether the wires are patent back to the controller. Write me for those details if necessary.
Roland