The fan will normally continue to run if the temperature is within certain limits, whether the key is on or not. This is normal. If the fan continues to run after the engine and radiator have cooled to warm to the touch, then the issue is either a stuck fan relay (sometimes a "jiggle" test will cure this) or a temperature sensor that is sticking closed until it gets to where the bimetallic strip inside it forces it to unstick. In this case, the sensor needs to be replaced.
How old is the battery? How long did the fan run this last time before the engine would not start for you? If it wasn't a very long time, you should also have the battery load tested. You *may* have lost a cell.
Check the connectors on the window switch for corrosion. Do the other windows run ok? What about headlights and tail lights with the engine off? What is the voltage on the battery after its sat for awhile?
You can check the temperature sensor with a multimeter set to check resistance. With the engine cold, it should read infinite resistance (open circuit). Once the engine warms up to operating temp, the switch inside the sensor should close (close to zero resistance). Once the switch closes, shut the engine off and keep the meter on the sensor leads and see if the switch reopens. If not, replace it.
If the switch operates properly, find the power out of the relay (usually pin 87, I believe) and see if the relay opens and closes properly.
One of these two items will be your problem.
Monday, June 13th, 2011 AT 6:04 AM