Radiator/cooling Fan Constantly On

wijcc · 16 Feb 2010 at 13:41

I had this problem before.. where the radiator fan constantly goes on/gives turning even after i switch off the car, draining my car battery. I resolved this problem about 2.5 months ago by fitting a new thermostat. However the problem has now returned again. So i am reduced now to disconnecting my car battery after i switch the car engine off.
Can anyone point me in the right direction as to what may be causing the fan to be constantly on??? Do I need to fit another new thermostat on?
The car is question is a 2001 Ford Focus 1.6 Ghia (mark 1)
Thanks in advance guys

sigma · 16 Feb 2010 at 13:43

There's usually a relay/fan switch that controls the fan. Should be able to test it easily enough!

wijcc · 16 Feb 2010 at 14:24

and how do you test it... i have no idea unfortunately

markweatherill · 16 Feb 2010 at 15:31

Don't know about Focuses but the radiator fan on cars is usually controlled by a thermo switch, separate from the thermostat and coolant temperature sensor.
They're not an expensive part (again, don't know about Fords!) and replacement would be a good test.

markweatherill · 16 Feb 2010 at 15:33

Ps until you solve the problem it might be easier to remove the radiator fan fuse than disconnect the battery each time.

wijcc · 16 Feb 2010 at 15:38

markweatherill said:
Don't know about Focuses but the radiator fan on cars is usually controlled by a thermo switch, separate from the thermostat and coolant temperature sensor.
They're not an expensive part (again, don't know about Fords!) and replacement would be a good test.

Thanks, is there another name the thermo switch might be called by.. as i can't find it in the haynes manual?

markweatherill · 16 Feb 2010 at 15:52

It might be called a Coolant Temperature Switch or Radiator Fan Switch or something.
In the electrical wiring diagram, if you can find the radiator fan, it should be nearby via a relay and fuse.

wijcc · 16 Feb 2010 at 16:25

I can find from the Haynes manual..
- radiator fan resistor assembly – which is secured to the top of the fan shroud
- cyclinder head temperature (CHT) sensor.. located on the engine near the spark plugs

From the wiring diagrams, engine bay fusebox fuses
F6 – engine cooling (air con)
F29 – engine cooling fan (air con)
F65 – engine cooling fan

BigglesPiP · 16 Feb 2010 at 17:40

It's either the temperature sensor or the relay.

Unplug the relay and test the impedance between the high tension terminals. If it's closed circuit buy a new relay, if it's open circuit buy a new sensor.

wijcc · 16 Feb 2010 at 17:46

BigglesPiP said:
It's either the temperature sensor or the relay.

Unplug the relay and test the impedance between the high tension terminals. If it's closed circuit buy a new relay, if it's open circuit buy a new sensor.

are you referring to the relay located in the fusebox?

BigglesPiP · 16 Feb 2010 at 17:51

wijcc said:
are you referring to the relay located in the fusebox?

Could be, I don't have a workshop manual for a Focus.

wijcc · 16 Feb 2010 at 18:01

found it... its a 30A relay/fuse... I took it out then put it back in and gave it a tap with the back of my torch and the fan stopped spinning.. so I guess I should really get myself a new relay/fuse???
Is that something you have to buy from a main/ford dealer?