Rad Fan Switch (sensor?)

[Bongo bus]

Can anybody advise where the Rad Fan switch or sensor is? Going from past experience I guess it would be good to change it every now & then to make sure the fan kicks in when it should?

Spencer

Ford Freda

[Grahame at work]

Hi Spencer,

The sensor is an RTD mounted in the block just above the starter motor.

It is connected into the ECU (Engine Control Unit) that uses the signal to affect other functions as well as the radiator fans.
I have not heard of anyone changing out this sensor as a matter of routine – you would loose coolant and have to go through a top – up process (if you have a spare finger to block the hole while you exchange it may be you would get away with it though!)
I looked at the cost of these sensors a while ago – the price ranged form nearly £40 down to about £15 if I took a chance on a non-Mazda equivalent that I couldn’t actually confirm was really the right part.

If the sensor is faulty the ECU should recognise it and produce an error code 09 which can be read on the diagnostics connector. I think that if it is faulty the ECU turns on the fans permanently.

A simple routine test is to turn on the AC and both fans should operate at a ‘low speed’ (normal speed) although this will be intermittent and dependent on the ambient temperature. When the fans are running disconnect the connector at the sensor (a little above the sensor and just below the inlet manifold) – this will switch both fans to ‘high speed’. You can tell this by the change in sound.

Hope this was helpful

Regards Grahame

[Bongo bus]

Hi Spencer,

The sensor is an RTD mounted in the block just above the starter motor.

It is connected into the ECU (Engine Control Unit) that uses the signal to affect other functions as well as the radiator fans.
I have not heard of anyone changing out this sensor as a matter of routine – you would loose coolant and have to go through a top – up process (if you have a spare finger to block the hole while you exchange it may be you would get away with it though!)
I looked at the cost of these sensors a while ago – the price ranged form nearly £40 down to about £15 if I took a chance on a non-Mazda equivalent that I couldn’t actually confirm was really the right part.

If the sensor is faulty the ECU should recognise it and produce an error code 09 which can be read on the diagnostics connector. I think that if it is faulty the ECU turns on the fans permanently.

A simple routine test is to turn on the AC and both fans should operate at a ‘low speed’ (normal speed) although this will be intermittent and dependent on the ambient temperature. When the fans are running disconnect the connector at the sensor (a little above the sensor and just below the inlet manifold) – this will switch both fans to ‘high speed’. You can tell this by the change in sound.

Hope this was helpful

Regards Grahame

Hi Grahame,
Thanks for the advice.I'll have a look the weekend & do the test. I've never heard the fans kick in...so I just wanted to be sure.
Thanks again & kindest regards
Spencer

Ford Freda

[dandywarhol]

Another quick way to test the fans themselves and wiring to them is okay is to switch on the a/c

[Rhod]

Dandy - will that work in current temperatures? I know that it was too cold for my A/C to switch on at the weekend

[dandywarhol]

Fair point

[teenmal]

Hi Spencer,

The sensor is an RTD mounted in the block just above the starter motor.

It is connected into the ECU (Engine Control Unit) that uses the signal to affect other functions as well as the radiator fans.
I have not heard of anyone changing out this sensor as a matter of routine – you would loose coolant and have to go through a top – up process (if you have a spare finger to block the hole while you exchange it may be you would get away with it though!)
I looked at the cost of these sensors a while ago – the price ranged form nearly £40 down to about £15 if I took a chance on a non-Mazda equivalent that I couldn’t actually confirm was really the right part.

If the sensor is faulty the ECU should recognise it and produce an error code 09 which can be read on the diagnostics connector. I think that if it is faulty the ECU turns on the fans permanently.

A simple routine test is to turn on the AC and both fans should operate at a ‘low speed’ (normal speed) although this will be intermittent and dependent on the ambient temperature. When the fans are running disconnect the connector at the sensor (a little above the sensor and just below the inlet manifold) – this will switch both fans to ‘high speed’. You can tell this by the change in sound.

Hope this was helpful

Regards Grahame

Hi Grahame,
I think that is worth a mention in a Fact Sheet.
Cheers Mal..