Radiator Cooling Fan Motor: Description and Operation

GENERAL OPERATION
Cars can be equipped with a 1-speed or a 2-speed cooling fan, which is situated behind the radiator and powered by an electric motor. A relay in relay position G in the distribution centre in the engine compartment is used for the 1 -speed cooling fan and for the 2-speed cooling fan when it is running at low speed. In relay position I in the distribution center in the engine compartment there is a relay which is used for the 2-speed fan when it is running at high speed.

The Integrated Central Electronics (ICE) module starts and stops the cooling fan at preprogrammed coolant temperatures, see illustration, by grounding the relays.

The ICE reads the temperature for 20 minutes after the ignition has been switched off and the cooling fan can run at low speed during that time for a maximum of 3 minutes.

WARNING: It can take several minutes before the fan is switched on. Therefore avoid touching the fan for at least 20 minutes after the ignition has been switched off.

For cars with an A/C system, the ICE starts the cooling fan at low speed when the pressure switch on the desiccant container closes, at about 16.5 bar. In certain hot countries there is an extra pressure switch, which closes at 22 bar. This means that the ICE starts the fan at a high speed.

If the conditions for high speed are met, the low speed will be connected for 2 seconds before high speed is switched on. In the same way the fan is switched from high speed to low speed for 2 seconds before it is switched off completely.





IGNITION KEY IN START POSITION

NOTE: Ignition switch terminals +15 ON and +54 OFF.

With the ignition key in start position the fan should, if it has been switched on, go from high speed to low speed and then, after 2 seconds, switch off completely.

If the fan's high-speed position is to be connected after the ignition key has been in start position, the low-speed position should be connected for 2 seconds and the fan should then switch to high-speed. A 2-speed fan can only be run at low speed when the ignition is switched off (+15 off and +54 off).

If the sensor shows readings outside the limit values -60 to -30°C (-76 to -22°F) or +130 to +160°C (+266 to +320°F) the ICE waits for 0.5 seconds, after which the cooling fan's low speed is switched on.



IGNITION SWITCHED OFF

NOTE: Ignition switch terminals +15 and +54 OFF.

When the ignition is switched off (+15 off and +54 off), the ICE measures the coolant temperature for 20 minutes. During this time the cooling fan could be activated, but only at low speed and for a maximum of 3 minutes.

With the ignition key in drive position (+15 on and +54 on3 the ICE measures the coolant temperature and the pressure in the A/C system to check the cooling fan.

The ICE receives information about the coolant temperature from the temperature sensor in the cylinder block.

This information is also sent to the temperature gauge in the main instrument.