coolant fan always on

[chris2008]

im having trouble with my radiator fan some times it comes on when i start the car up from cold, some times its on low and some times it runs on high, the temp in the car on the clock is normal, what could be the problem?

i dont want to take it to the garage if its somat i can do my self

cars a:
megane hatch
1.5dci 100 expression 2005 model


i've just found this online (this is the same symtoms)

Question:
1.5 dci scenic 2 (04) radiator fan switches on when engine cold, not always, sometimes slow speed sometimes fast. usually on within 5-10 secs of starting up. Not always on when engine hot but hit & miss. Water temp gauge ok, tried disconnecting this but same result. My Renault service garage has reset ECU etc. but says they are baffled & will call me when they have contacted Renault! 1week later I still have'nt heard anything.

someone says:

Accepted Answer
<p>the aircon sensor wiring is more than likely corroded causing a short circuit and hence turning on the cooling fans would have it checked out. the sensor is in front of the aircon compressor going into the evaporator(radiator) it is a three pin sensor. hope this helps Johnny</p>





does anybody agree?

[AlexB]

Check the temperature sensor on the block. It has two sensors inside, one for the ECU/dashboard and one for the fan. Please check this info for your particular model, but I am fairly sure that this might be the case. There are the electrical diagrams in Links. The aircon, as I know, does not control the radiator fan.

[chris2008]

Check the temperature sensor on the block. It has two sensors inside, one for the ECU/dashboard and one for the fan. Please check this info for your particular model, but I am fairly sure that this might be the case. There are the electrical diagrams in Links. The aircon, as I know, does not control the radiator fan.

ive located the sensor how do i get it off ? ive pulled the connector off it i just need the sensor off haynes manual says i have to empty the coolant system, dont tell me i have to do that is there any other way of doing it?

[AlexB]

I don't know, I am not an expert. See if it is possible to plug the hole quickly and then top-up half a litre. On the other hand, the coolant must be changed every four years anyway...

[chris2008]

stuiped question, where can i get one from i know RENAULT, but how much are they about £5?

[AlexB]

Ring Renault parts and ask to quote the price and the part number. Alternatively, anyone with Dialogys at hand can do it. Then type the part number in Google... There is always an option to ask your friendly local garage to order the part with their trade discount. Check the GSF catalogue (can be downloaded), as Freddy suggested. You are not the first with this problem -- there will be more suggestions.

stuiped question, where can i get one from i know RENAULT, but how much are they about £5?

[chris2008]

finaly got round to order the part from renault gonna cost me arround £25 for the sensor what a rip off , it best sort the problem out, does anybody know if it dont work can i take the part back for a refund?

[chris2008]

i have the sensor for sale if anybody wants it

its on ebay for £17


item number is 320429618960 its a renault part,

[Alhozine]

I am still struggling to understand why the fan is still on even if my Megane Diesel engine is still cold and the temp gauge on the dashboard stays on the cold side despite the engine warming up and I took it on a long drive loaded with 80 kg luggage , the needle did not go up the hot side !!! What's going on with this crazy car ???!!!

[Alhozine]

Youtube mechanics say it's the engine block temperature sensor , I removed it , and tested it in my kitchen using boiling water to check if its resistance goes up and down as it should according to water coolant temperature in the engine. It did exactly as the one with the Youtube Mechanic guy .
So where is the fault then ? My handset diagnostic tool picked up an OBD2 Code P0115 , and it's the same sensor !
I also have a strong smell fuel from exhaust pipe which I know is NOT gonna pas the emission test . I plugged my diagnostic tool and it told me it's Code P0487 EGR Generic Current Electronic Throttle control Circuit A OPEN !

Can anyone generous help me pass the Emission Test please ?