Hi I wonder if anyone out there can help me. I've got an 03 Octavia 1.9 tdi and both fans run constantly when the ignition is live whether the car ir running or not.

When I got the car last August we had a temperature problem aswell or the fans running, we replaced the headgasket and radioator and sorted the temperature problem but this problem with the fans is really starting to annoy me now, Ive disconnected both fans for the moment but was wondering if anyone knows what the problem is?

Many thanks,

Lindsey

CTS (Coolant temp sensor) failure is extremely common, & would be my first suspect followed by the rad sensor. If the CTS output to the ECU has failed it could think the engine is hot so is turning the fans on.

If you haven't got access to VCDS to be able to see the temp the ECU is getting from the CTS. Check to see if you have the old black type sensor (notorious for failing), & if you do replace it with a genuine revised VAG green sensor as it will fail if it hasn't already.

BTW at least one of the fans should always come on if the AC is on.

It could be a faulty air conditioning pressure sensor, constantly showing a high pressure.