3 Speed radiator fan wiring diagram.

Hurricaneplanes · 23rd April 2012, 07:15

Hi there, Can any one please let me have a wiring diagram for a three speed radiator fan showing clearly the colours of the wires and also identify which part of the circuit controls the slow, middle and fast speeds. The reason for this is that the mechanic who replaced my fan with another 3 speed fan disconnected all wires from the control box including the wires from the multipin connector. I want to find out whether the cause of failure was the fan or the control box and hopefully get this unit up and running as a spare for the future.
Thanking you in advance for your help.

SD1too · 23rd April 2012, 08:14

James,

That's quite a question because the circuit is quite complex and the MG Rover version includes an error. I would say though that it's 99% certain that your previous 3 speed fan failed due to excessive wear of one or two of the motor brushes. The best course of action is to remove the motor end plate and have a look. There are plenty of threads to help you with this.

Simon.

lovema75 · 23rd April 2012, 11:24

You dont specify if your car is petrol or diesel, the control boxes are different for each. However I believe the motor is the same for either.

If your car is petrol then the following may help. It seems the reason for 3 speed fan failure is often worn brushes, so if the motor isnt too badly worn you could try the following:

Remove the motor end plate and remove the mounting plate for the brushes, it looks like this...

Most likely the low speed brushes will be worn out. If you have the power wires on your left the low speed brushes are the 2 on the right. You can buy replacements from Ebay £10 for a pack of 2. My own high speed brushes (the 2 on the left) were hardly worn so I left mine.

It is fairly easy to solder in the new brushes. Then using a WD40 cap to hold all 4 brushes fully retracted refit the mounting plate into the motor and replace the end cap.

If your car is petrol then try the motor directly fed from the battery into the control box using the following wiring diagram:

If your car is petrol and you wish to test the relays in the control box, then supply power to the connecting plugs as shown here...

...direct from the battery using the following wiring scheme:

This will cause the fan to run at full speed, and because all 3 relays are used to achieve this it will confirm that they are working. Only do this for a few seconds as the power consumption is considerable.

If your car is diesel or the wires are a different colour do not use the above diagrams!

craig8661 · 23rd April 2012, 12:13

see the diagram for the 4 wires that should be the same for the diesel can any one confirm that the abouve picture is right as the diagram i have from here is saying the purple is to go to positive for the high speed

Steve916 · 23rd April 2012, 12:53

Looking at that diagram Craig, I would have said that the purple needs to go to positive to bring in the 3rd relay but I'm sure somebody with a 3 speed fan can confirm this

stocktake · 23rd April 2012, 12:57

The purple is indeed a second neg, the rover guidelines on this are incorrect. Remember the diesel is a different setup from the second "diagram"

this as apparent as the relay box incorporates a PCB

The test for the bare motor are however the same

as shown in "diagram 1"

craig8661 · 23rd April 2012, 12:59

what would it be with out the relay box i have a 3speed and want to test it i have the relay box on but would prefer to test both ways

stocktake · 23rd April 2012, 13:02

Quote:

Originally Posted by craig8661

what would it be with out the relay box i have a 3speed and want to test it i have the relay box on but would prefer to test both ways

without the relax box, the testing for the three speed fan motor only petrol or diesel is as per the first diagram

FrenchMike · 23rd April 2012, 13:02

3 speeds diesel schematic:

Ventschema.jpg

Mike

Hurricaneplanes · 23rd April 2012, 13:04

Hello again, I am sorry that I did not state that the engine is the 2lt diesel dated 2001.I wrongly assumes that in the interests of economical car production that the same coloured wires to the fan would be the same for all 3 speed fans. Sorry if I have mislead people. So now the question I should have asked is for a wiring diagram, including wire colours for a 3 speed fan for a 2 lt diesel engine and indicate the correct wiring for slow, medium and fast speed. So please can anyone help?
Many thanks in advance.

23rd April 2012, 07:15	#1
Hurricaneplanes Avid contributor Rover 75 Tourer 2Lt CDTI Join Date: Nov 2011 Location: Solihull Posts: 178 Thanks: 19 Thanked 4 Times in 3 Posts	3 Speed radiator fan wiring diagram. Hi there, Can any one please let me have a wiring diagram for a three speed radiator fan showing clearly the colours of the wires and also identify which part of the circuit controls the slow, middle and fast speeds. The reason for this is that the mechanic who replaced my fan with another 3 speed fan disconnected all wires from the control box including the wires from the multipin connector. I want to find out whether the cause of failure was the fan or the control box and hopefully get this unit up and running as a spare for the future. Thanking you in advance for your help.

23rd April 2012, 08:14	#2
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,382 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	James, That's quite a question because the circuit is quite complex and the MG Rover version includes an error. I would say though that it's 99% certain that your previous 3 speed fan failed due to excessive wear of one or two of the motor brushes. The best course of action is to remove the motor end plate and have a look. There are plenty of threads to help you with this. Simon. __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

23rd April 2012, 11:24	#3
lovema75 This is my second home 75 Tourer CDT Join Date: Dec 2011 Location: Enfield Posts: 3,925 Thanks: 63 Thanked 431 Times in 237 Posts	You dont specify if your car is petrol or diesel, the control boxes are different for each. However I believe the motor is the same for either. If your car is petrol then the following may help. It seems the reason for 3 speed fan failure is often worn brushes, so if the motor isnt too badly worn you could try the following: Remove the motor end plate and remove the mounting plate for the brushes, it looks like this... Most likely the low speed brushes will be worn out. If you have the power wires on your left the low speed brushes are the 2 on the right. You can buy replacements from Ebay £10 for a pack of 2. My own high speed brushes (the 2 on the left) were hardly worn so I left mine. It is fairly easy to solder in the new brushes. Then using a WD40 cap to hold all 4 brushes fully retracted refit the mounting plate into the motor and replace the end cap. If your car is petrol then try the motor directly fed from the battery into the control box using the following wiring diagram: If your car is petrol and you wish to test the relays in the control box, then supply power to the connecting plugs as shown here... ...direct from the battery using the following wiring scheme: This will cause the fan to run at full speed, and because all 3 relays are used to achieve this it will confirm that they are working. Only do this for a few seconds as the power consumption is considerable. *If your car is diesel or the wires are a different colour do not use the above diagrams!* Last edited by lovema75; 23rd April 2012 at 11:30..

23rd April 2012, 12:13	#4
craig8661 Posted a thing or two rover 75 tourer cdt Join Date: Feb 2011 Location: Chesterfield Posts: 1,924 Thanks: 3 Thanked 4 Times in 4 Posts	see the diagram for the 4 wires that should be the same for the diesel can any one confirm that the abouve picture is right as the diagram i have from here is saying the purple is to go to positive for the high speed __________________ http://i984.photobucket.com/albums/a...y%20se/sig.jpg spoilt as i own a cdt auto connoisseur se cdt auto member 829 mods so far synergy 2 heated washer jets cant really add anything else as it has it all lol

23rd April 2012, 12:53	#5
Steve916 This is my second home Rover 75 1.8 Connoisseur SE and a Ford S-Max Titanium Join Date: Jan 2012 Location: Huntingdon Posts: 3,756 Thanks: 70 Thanked 31 Times in 27 Posts	Looking at that diagram Craig, I would have said that the purple needs to go to positive to bring in the 3rd relay but I'm sure somebody with a 3 speed fan can confirm this __________________ Mods so far: Plenums, bonnet release mod, handbrake compensator (arctic), rear parking sensors, coolant level sensor (Vindaloo), DRL's, Fan resistor upgrade ( Jules), Marmite lighting, Auto dimming rear view mirror, twin horns, fog lights, real walnut dash, walnut gear knob, Sean DD unit with DVB-T, message centre ipk, electric sun blind, auto opening boot lid, walnut steering wheel, electric seats Link to my Auto Boot Lift Mod http://www.the75andztclub.co.uk/foru...d.php?t=114273

23rd April 2012, 12:57	#6
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,591 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	The purple is indeed a second neg, the rover guidelines on this are incorrect. Remember the diesel is a different setup from the second "diagram" this as apparent as the relay box incorporates a PCB The test for the bare motor are however the same as shown in "diagram 1" __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident Last edited by stocktake; 23rd April 2012 at 13:00..

23rd April 2012, 12:59	#7
craig8661 Posted a thing or two rover 75 tourer cdt Join Date: Feb 2011 Location: Chesterfield Posts: 1,924 Thanks: 3 Thanked 4 Times in 4 Posts	what would it be with out the relay box i have a 3speed and want to test it i have the relay box on but would prefer to test both ways __________________ http://i984.photobucket.com/albums/a...y%20se/sig.jpg spoilt as i own a cdt auto connoisseur se cdt auto member 829 mods so far synergy 2 heated washer jets cant really add anything else as it has it all lol

23rd April 2012, 13:02	#9
FrenchMike This is my second home Rover 75 Saloon Join Date: Aug 2007 Location: Avignon Posts: 4,466 Thanks: 94 Thanked 661 Times in 554 Posts	3 speeds diesel schematic: Ventschema.jpg Mike Last edited by Dragrad; 17th June 2014 at 21:48..

23rd April 2012, 13:04	#10
Hurricaneplanes Avid contributor Rover 75 Tourer 2Lt CDTI Join Date: Nov 2011 Location: Solihull Posts: 178 Thanks: 19 Thanked 4 Times in 3 Posts	Testing a 3 speed fan Hello again, I am sorry that I did not state that the engine is the 2lt diesel dated 2001.I wrongly assumes that in the interests of economical car production that the same coloured wires to the fan would be the same for all 3 speed fans. Sorry if I have mislead people. So now the question I should have asked is for a wiring diagram, including wire colours for a 3 speed fan for a 2 lt diesel engine and indicate the correct wiring for slow, medium and fast speed. So please can anyone help? Many thanks in advance.