Chrysler Repair: cooling fan runs all the time while engine is on, powertrain control module, coolant temp

Question
Starting today (raining) my cooling fan on my 2001 3.3 dodge caravan sport is staying on while the engine is on , i have replaced the cooling fan relay located on the inside of the front left bumper , and the problem is still there , i have hooked up a scanner and iam able to manually disable the fans , any idea what this could be i have done some research on identifix a webstite for automotive repair shops, and there was mention of a pcm (powertrain control module) i hope this is not it.

Answer
Hi Trevor,
It could be that the coolant temp sensor is inaccurate and telling the pcm that the engine is hotter than it really is. It is located near the thermostat houseing and has 2 wires: violet/orange and dark blue/dark green. When the engine is cold it should read 7000-14,000 ohms across its terminal (plug removed) and when the engine is warm it should read 700-1000 ohms. If it is reading less than 700 and the engine is not approaching 'hot' on the gauge, then the sensor should be changed. You also could check that the violet/orange wire is not shorted to a 5 volt supply voltage or disconnected/open between the plug and pin 28 of the pcm which is where it is routed. It carries the signal that tell the pcm how hot it thinks things are. The pcm is under the hood, directly behind the radiator and next to the battery.
Roland