Chrysler Repair: 95 Intrepid Cooling Fans run all the time, upper radiator hose, coolant temp

Question
My son just bought a 95 Intrepid and the cooling fans will not turn off.  The engine is not overheating.  I removed the fuse and the fans turn off.  I also tried swapping the relays but nothing changed.  The fans begin running if you turn the ignition switch power on.


Answer
Hi James,
I would be inclined to believe that the coolant temp sensor is not reading an accurate resistance, or its plug is disconnected. It is located next to the upper radiator hose manifold at the top front of the engine and it has a tan/black wire and a black/light blue wire.
If it is unplugged the fans will run; if it reads a resistance of around 500 ohms or less it will also cause the fans to run. Normally it should read 7-10,000 ohms when cold and then drops to below 1,000 as the engine warms up, finally going low enough to tell the module to turn on the fans.
If that is not the case, then I would check the wires from the powertrain module on pins 31 and 32 of the 60-way plug that go to the high and low speed relays to see if they might be shorted to ground when the 60 way is unplugged to see if they are grounded. They are dark blue/pink and white, respectively. The module is what grounds those wires when it "sees" high coolant temp but if the wires were shorted to ground all the time it would be the same thing.
Roland