Cooling fan is on while vehicle is not running

dodge
grandcaravan

#1

My cooling fan in my 04 grand caravan operates when the vehicle is turned off and while it is on as well. The fan will stay running and the only way I can turn it off is by unplugging the fuse for it in my fuse box. I replaced the fan relay but the problem is still there. I need this fixed in order to prevent over heating while idling or in traffic which has happened a few times because I removed the fuse for good in order to prevent my battery from dying while the car is off. Any ideas will help.


#2

The next thing to check is the coolant temp sensor for the fan.

Not the one for the computer or the gauge/light.

Tester


#3

Tester https://community.cartalk.com/u/tester
April 13

The next thing to check is the coolant temp sensor for the fan.

Not the one for the computer or the gauge/light.

Tester

Thank you I will look into this. Much appreciated


#4

The radiator fan relay is mounted on the front bumper, is that the one you replaced?


#5

Nevada_545 https://community.cartalk.com/u/nevada_545
April 13

The radiator fan relay is mounted on the front bumper, is that the one you
replaced?

Yes


#6

I appreciate your problem, but allowing the car to overheat can cause extensive damage and very expensive repairs.


#7

Did you not read the title?

The radiator fan runs all the time?

Tester


#8

except he took the fuse out, and he has seen overheating in traffic.


#9

From what I see, the way it works (on the v6 3.3L 04 GC), the radiator fan relay is controlled by the engine computer. The engine computer uses a digital signal to control the fan speed; the fan speed depends on the width of the digital pulse sent to the fan relay by the engine computer. The engine computer decides the fan speed (and hence the pulse width) based on the engine coolant temperature, AC on or off, intake air temperature, vehicle speed, and transmission oil temperature, along w/ other parameters.

Since you’ve already replaced the relay, one idea is the engine computer signal is shorted out or disconnected in such a way the relay thinks the fan should be on 100%. I tend to think that’s what the problem is, b/c you say the fan runs even when the engine is turned off and the car is parked. Beyond that, make sure all those other sensors are working. Is the check engine light on? Have you read out the computer diagnostic codes yet? If not, that’s a good place to start.

Another idea, there may be a designed-in fail safe so the fan runs at full speed if the fan relay every becomes disconnected from the engine computer. Check the pertinent connectors for burned, damaged terminals. My Corolla’s radiator fan works like that. If the connector to the fan control temp switch get disconnected, the fan runs all the time. It doesn’t run when the engine is off though.


#10

I am trying to clearly understand your post. The fan on these are supposed to run after the car was shut off if the engine is hot. Are you saying your fan runs all the time, even an hour or more after the car is shut off?

If so you need a new fan controller or it is sometimes called a fan control module/. It is not in the under hood power center and has a heat sink that looks like little aluminum towers. It is located on top of the steel bumper under the bumper cover on the drivers side of the radiator. Is that what you replaced?


#11

yes that is what I replaced and my fan runs non stop yes.


#12

Then it would seem that the control wire is shorted to ground. If I recall correctly those fan relays were riveted to the bumper, did you attach the replacement relay with rivets or screws?


#13

Or your new controller is bad. I am not sure how to test it. Maybe someone can help.


#14

It was one screw. The problem is fuxed I just replaced the relay thanks for the help.


#15

?? In your OP you said you had already replaced the relay. Was the first relay replacement faulty then? And a second relay replacement fixed the problem? If so, getting faulty replacement parts is definitely not an unheard of thing here.


#16

Yes I believe it was faulty. It’s fine now and fan works right but my overheating light will go on even if I blast my heat and the fans are on. The engine will be cool but overheating light will turn on and begin to ring


#17

Glad your engine fan is working now. The overheating light problem might be

  • the engine actually is overheating, for which there are a variety of reasons. a coolant system pressure test would be a place to start for that.
  • the sensor which turns on that light is faulty
  • air in the cooling system
  • the fans are turning when they are supposed to, but at too slow of speed for the cooling demand situation. as I recall that design is able to turn the fans at both a low and high speed, the speed directed by the engine computer.

#18

I’ll have to test these out. Thank you so much


#19

Best of luck. Cooling system problems can be very frustrating.


#20

Yes I agree thanks a bunch