My thermal fan always runs!

I've had this 'problem' since I bought my zed, the thermal fan is ALWAYS on no matter how warm or cold the engine is, the auxillary fan works fine, but the thermal fan is constantly on.

First let me tell you that my A/C pulley has no belt on it, and hasn't since I bought the car. I'm not sure why as the compresser is fine, but its never bothered me either way, I didn't want to have to try and play around with belts for the sake of a bit of cold air.

Now this had us stumped for quite some time but then chris (rom-vg30dett) came up with the idea that the harmonic balancer might be the culprit in this conundrum, something about it knowing how many pulleys should be turning? Does this sound right? are we even close to being 100ft from the right track?

If its right, any suggestions
If not, any suggestions?

Thanks
Nick

 

I'll bet thermo-fan was wired direct/always on with IGN due to a/c failure and belt removal.

 

I can tell you now the ECU does not have a clue of how many belts are attached to the crank shaft pulley.

The factory thermo fan in front of the condensor is switched by the ECU only under special conditions depending on temperature or temperature and speed. The twin turbo fan actually has a high and low speed.

The only other way that the electric thermo will constantly run is if the ECU has detect a fault with the coolant temperautre sensor, I think it is code 14. Do a self diagnostic on the ECU to find this out and if this code is present, clean the 2 terminals on the CTS and the plug. If there is no fault present it will likely be as K-zed has mentioned.

 

yeah i've done a number of diagnostics, ran conzult and datascan and never had anything but 55, I've even checked my CTS just incase and it was clean as a whistle, so I'm guessing it's what K-zed mentioned, is there any way of reversing this? it annoys me to death

 

Mine kept kicking in

when i took it for a service i was told that the fan was kicking in all the time due to the sensor at the front which was cleaned up and now it doesnt happen anymore so yeah id prob trust K-Zed more than me but thats what happened with mine so maybe....

 

change the coolant temp sender nick,probably is that

 

I wired mine to run all the time

I just pull the earth wire off the relay I installed to run it in the cooler weather.

 

or u could just connect it up to a switch, flick it on for hotter days....

 

Yeah i have the same problem. Ive check the voltage comming out of the sender unit and it was correct for that temp. I cleaned both sides of the terminal but it still constantly runs.

I guess replacing both the sender and the connector must be the go?

Any ideas?

Cheers
Steve

 

Is it possible that the Sub Fan relay has stuck on? You could test this by removing the relay and see if the fan stops and then put another relay in it's place and see if it runs.

 

So where do I find this sub fan relay?

 

Fuse box, front passenger side of engine bay. There is another relay that says from memory Rad Fan, this controls I think the low speed of the fan on a TT. I have found on numerous occasions that one of these relays is missing, even on mine.

 

the subfan relay is missing from mine so yeah hehe

 

Yeah.. I notice i am missing the sub fan relay.

So all this means is the fan in perm. on?

So now still trying to figure the fuel consumption. I will only get 400kms to a tank of very mild driving. This normal?