Radiator Cooling Fan Control Relay.

[zola1]

Hi,

 

Can anyone help with :-

 

I have a 53plate 1.9 tdi (with air con).... i would like to locate the cooling fan control relay and fit a toggle switch to bring in the fan independently of the engine thermal switch.

 

Has anyone got a circuit diagram of the relay (e.g is it a conventional relay that i can either switch with a +12v to bring in or does it switch to gnd)

 

Any help or tips on the kind of circuit control that is used would be much appreciated.

 

cheers

[chrispb123456]

Hi there and welcome to the forum

I can send you a diagram of relay 430, but am curious as to why you would want/need to do that.

This is not a straight forward system for controlling the fans a lot of other circuits are wired through this relay (has about 12 terminals on it) and rely on it to work correctly.

[zola1]

hi,

 

a copy of the wiring diagram would be great can you post it or pm me.

 

i would like to have some manual control over the rad fan, i do a lot of stop start and whilst the fan does cut in and out ok it'll give me peace of mind : )

 

is it a modulated control of the fan motor ?...all i want to do is turn it on and off...

 

I know that if it is a high torque start motor there may be issues..please advise ?

 

many thanks

[chrispb123456]

Hi again

Will need to know your engine code eg, ANU, AUY, ASZ, ARL. and do you have the digital display panel or the three knobs controling heating.

You will need to PM me your email address to send it.

[Mirez]

I think you'll have issues full-stop. Firstly the fans are 2, 3, or 4 speed variable by the controller so they'll only receive the full 12V at full speed (which is loud). Secondly the controller isn't a simple relay affair so applying 12V further down the line to put the fan on will need a suitable sized diode introduced to stop back voltage damaging the controller.

[zola1]

I think you'll have issues full-stop. Firstly the fans are 2, 3, or 4 speed variable by the controller so they'll only receive the full 12V at full speed (which is loud). Secondly the controller isn't a simple relay affair so applying 12V further down the line to put the fan on will need a suitable sized diode introduced to stop back voltage damaging the controller.

[/quote

 

 

hi,

 

Good info thanks,

 

so as i understand it(please correct me if i've got all wrong)..the controller uses an internally generated pwm signal to give different speeds of the motor shaft possibly 3 different speeds up a full +12v which gives the final FULL speed ......how does it know the temp of the coolant and then decides to give the motor the relevant speed to turn??

 

if i decide to go for a switch that will only supply +12v to the control wire the diode needs to in-line of the motor control wire to the fan pack and the +12v can ONLY go in ahead of the block side of the diode ?

 

hope this makes sense.

 

many thanks for the tech update

[zola1]

I think you'll have issues full-stop. Firstly the fans are 2, 3, or 4 speed variable by the controller so they'll only receive the full 12V at full speed (which is loud). Secondly the controller isn't a simple relay affair so applying 12V further down the line to put the fan on will need a suitable sized diode introduced to stop back voltage damaging the controller.

[/quote

 

 

hi,

 

Good info thanks,

 

looking at the circuit i got from chris the rad fan relay receives 2 separate inputs...

 

1). +12v (green wire) from the rad fan 2nd speed relay (i note that this input is in parallel with a signal from the fan thermo sw)so dependant upon weather the air con is on or off a fan will be on with air con on all the time or coolant temp controlled via the thermo sw.

2). +12v (red/white wire) from the thermo sw & in parallel with an output from the rad fan controller.

 

so if i wire in two diodes in-line of the red/white and green wire to prevent the +12v going back down the control wires, i could then input the separate +12volts via fused switches at the relay and achieve manual control over both fans ?

 

does this add up ?

 

cheers