Hey guys, I've got a 4cyl dakota manual with an electric fan problem. The fan works and comes on when the vehicle is running but will not engage when I stop and turn the truck off. This is causing it to get hot and sometimes not allow me to restart it. Wondering if anyone has any insight. Thanks

 

could be the relay isn't staying energized, the thermostat that tells the controller to turn the fan on could be bad, the controller could be bad (looking at auto zone they list a controller, but not sure if it's for factory or after market fan). Does the fan cycle off with a/c off? does it only run with a/c on?

 

The fan comes on with the a/c on and also when it gets up to temp while driving just not when the vehicle is shut off after a drive. This resulted in the water pump going out and needing replacement fairly recently. When they did the pump they did the thermostat as well and I later changed out the temp sensor attached to the thermostat housing and the relay too. I'm stumped. I've looked to see if there is another sensor but can't find anything that says there is. I thought maybe it was insufficient power while shut off but Thad the battery, alternator, and starter tested and all is well. Not sure if it is related but there is also a problem with surging rpm's while driving.

 

might be the controller then, should have power available with key off

 

the fan on our trucks, to the best of my knowledge, always shuts off with the PCM when the key turns off. The fan will not run with the engine off. Unless the water pump is turning, the water is not moving in the system so the fan being on is pointless***. It's not related to the water pump going out.

*** I have my radiator fan hotwired to a dash switch, and I run the lincoln Mark8 fan. With the engine off and water pump not moving, I can get the water in the radiator down from 190 to 178 in about 5 minutes. I usually run the motor for 15-20 seconds and shut it back off again to rotate the water through the cooling system, and repeat after 5 minutes. It works but is not quite enough between rounds, so I am currently mounting up an electric water pump drive, but it is not street rated.

 

never had an electric fan on my trucks, but on my cars, and my mom's vans the fans would run for about 5 minutes after key off (usually a warning sticker on the core support about it too)

 

I'm familiar with the sticker. But on our trucks, the PCM shuts down at key off, thus the fan does as well, to the best of my knowledge. I run my lincoln fan off the stock pigtail for A/C purposes and it never stays on unless I flip my dash switch. As I stated, unless the water pump is turning, it really does no good other than to drain the battery.

 

Thread moved to regular forum.

 

Yes engine off fan off that's how it works on the 2.5

You have a different problem I'm guessing a bad rad or thermostat or your not using the correct ratio of antifreeze or the wrong stuff.

 

Yes, there is no specific purpose in it turning on while the car is off.
The fans simply turn on based on temperature. If the thermosensor detects temps, say above 210 degrees or so, the fan turns on, whether vehicle is off or on.