Radiator cooling fan staying on

[ConroeS4]

Well my parents came and got me up this morning saying my radiator cooling fan is staying on. It comes on at low speed, idles, revs up to high speed, then goes back down to low speed, then shut off. It's been doing this intermittently and stays on for a minute or two. The car hasn't been driven in over 9 hours, and it's 75 degrees here and wet with no sun. I also started the car and shut it off and it's still doing this. Any idea what's wrong?
Thanks
Cameron

[500HPS5]

It is the FMIC

[ConroeS4]

say what?

[gtsingh91]

same thing happened to my cousins 2005 A8 and he replaced the thermostat, water pump, and timing all at the same time, but i think the culprit was the thermostat

[Mark]

might have water in the ecu or the radiator fan control unit is bad or has water in it. could be coolant sensor as well.

[JEENYUS]

if you look on the front of your car (under the hood) it states:

CAUTION! RADIATOR FAN MAY TURN ON AT ANYTIME. KEEP HANDS CLEAR!

it reads more or less as that. I would talk to the dealer and see why, it might just be hot as hell. I would check that out and see. sometimes the car just does that to cool off.

[JEENYUS]

OBS: i doubt that it is water, it gets so hot and these car (well at least mine) can handle a lot of water before anything ever happens...


<<<<proof of this

[FLultrasport]

i had the same thing hppen to me you might want to disconnect your battery before it kills it, i took it into the dealer and they said the engine coolant temp sensor was broken so the car thought the engine was over heating even tho it wasnt on, luckily i had a warrenty on it so i didnt have to pay that much but i dunno what it will be like for

[500HPS5]

On the real it is the green coolant temp sensor, about $16 to fix.

[FLultrasport]

they swapped out a few parts tho i think i dont know what all is involved with it

[mtbrider]

On the real it is the green coolant temp sensor, about $16 to fix.

I second this..

[diagnosticator]

This is a common symptom of water in the ECU compartment. You should remove the cover and visually check for water inside, doing so will either rule out the possibility, or reveal the cause of the fan running erratically with a cold engine and the ignition OFF.

[ConroeS4]

If there is water in the ecu how bad is that?

[diagnosticator]

If there is water in the ecu how bad is that?

If visual inspection confirms water inside the ECU box, it depends on how much water and how long it has been leaking into the ecu compartment. The parts typically damaged are the several relays and fuses inside. The engine ECU itself is high enough, above the relays, to not get wet. The relays and fuses need to be replaced, and the cause for the water leak into the ECU box identified and fixed for sure.

[jackyaudi]

When I removed the fuse for the radiator fans (cannot remember why at the time), the fans kept on running as long as the car was. You would think they would stop, but it was the opposite. Maybe check that fuse?

[cody23]

Hi guys! I'm new here and new to this car stuffs.. At first I wasn't really interested with cars, it's only now that I become interested. So please be good to me. LOL Actually, I think I'm experiencing your problem now with those radiator cooling fan. I didn't know it has something to do with the thermostat. I thought of just replacing it and buying this dual cooling fan oe style for radiator. But I'm glad of all the information I got from this. Thanks! There's a lot to learn!