Fan will not run when hot

Over heating the engine is a serious concern. With the hood raised you should hear the motorized fan turn on just behind the radiator as the engine requires additional cooling.. If you look in from the rear of the radiator you should see the fan blades.

This electric powered motor operates on a thermostat and when the engine temperature rises this fan should come on. I'm assuming from your description that when driving and air is flowing through the radiator as the car travels the engine is nor overheating.

Check fan motor thermostat, check fan motor and check wiring.

Wiring Diagrams related to the Honda Civic
http://www.wiringdiagrams21.com/category/automotive/honda-automotive/civic

Motor engine cooling fan only runs as engine temperature requires additional cooling.

Most likely the clutch fan or water pump. Just did BMW clutch fan. At idle it was turning fast. You could reach down and stop it with your hand. I don't recommend doing this though.

you can disconnect the electrical plug on the rad cooling fan/s and run jumper wires directly to the motor contacts from the battery if it does not run replace the cooling fan motor. if the motor runs then check for a bad cooling fan relay. this is were its best to have a scan tool as you can see the coolant temp of the engine and the computer commanding the cooling fans to come on. if the computer commands the fans to come on then you have eliminated 2/3 of the system working.

Is the engine actually cooling off? If the temp switch isn't seeing a drop in temperature, it will keep the fan running.

Check the coolant temperature with the car stopped. At idle with the hood up keep the thermometer in the coolant. Confirm if the coolant is not overheating but the engine is!!

Run the A/C keeping the thermometer in the coolant and allow the fan to kick on.

If with the A/C on the engine doesn't overheat then it confirms that the low speed on the fan motor is not working. Read the description of the Taurus where the low speed is used for normal operation when temperature is required but the high speed is activated when the A/C is on. The circuit is simple.

In your case the low speed has to be activated for the A/C to go into the high speed. The fact that the high speed is working and low speed is not indicates the low speed of the fan is defective.

Other problems such as the thermostat or plugged cooling system(radiator clogged) could be the root problem!

Hope this helps?

WELL ON THE TALON AND ALOT OF OTHER CARS LIKE IT SOMETIMES IT WOULD BE BETTER TO RUN YOUR FAN TO A TOGGLE SWITCH ALSO WAT IT SOUNDS LIKE IS YOUR THERMOSTAT MIGHT BE GOING OUT AND IF THERE IS A CHECK ENGINE LIGHT ON YOU CAN TAKE IT TO ADVANCE AND THEY WILL DO A FREE DIAGNOSTICS FOR YOU

cOOLING fAN tURNS ON @ 210-230 dEG. tEMP sENSOR bAD & OR fAN relay cAN cAUSE THIS pROBLEM

The radiator cooling fan relay has most likely failed. It is underneath the air cleaner on the frame rail just behind the radiator. NO cooling fan = overheating. This is the first thing i would look at. Best way to tell is when the van gets hot see if the cooling fan is on. You will hear it running if it is coming on. It will set a code for the cooling fan relay also.

it sounds like your radiator fan is not working. once your engine reaches a certan temp. the fan should come on to cool it down. also might be the thermostat is not opening. it is not good for the motor at all to over heat and stall. you could ruin your engine. i would change thermostat first and then run it till it starts getting hot to see if the fan kicks on. if it doesn't, it could be the coolant sensor or the fan itself. good luck.

Cooling Fan Malfunction. Your radiator fans are most likely not working. That's why the temperature is OK when you're driving full speed and the wind is cooling your radiator. You need to check and/or replace your cooling switch module and radiator fans (most likely it's the cooling module). If you were sitting idle or in stop-n-go traffic for an extended period of time, your car WOULD overheat because the fans aren't kicking in cooling your radiator - then you would see all of the cooling system water spill out of the coolant reservoir, before this would happen your temperature gauge would go to the red and the digital dislpay would flash a thermometer (indicating you're about to overheat in 2 mintues). I hope this helps someone out there - Yes, it happened to me in the middle of nowhere.