Radiator Fan Replacement Question

[Dronix]

Hi there guys!

Here in Russia we have a Rovers too, and due to hard climate we have a lot of problems, but damn I love this car!

And here's the problem.
I have a 3-speed fan now, and it seems to be dead. I checked connectors, it has necessary voltage, but fan doesn't rotate.
On the other hand, I have a 2-speed fan, that I know it works, I have a 100wt resistor too. But, I don't have a relay block from this 2 speed fan. As you can see from my intro, I'm from Russia and I can't find 2-speed relay block separately here and on eBay also. I think it's not a big deal to make it by myself, using relays from my dead 3-speed fan. But, to do that, I would like to see electric scheme from 2 speed fan with this block.
Do you guys have one? Or can you make a simple sketch, please?

Yes, yes, I know, I should remove bumper etc. and see what's wrong with 3 speed motor, but I don't have much time and a warm garage (have you ever tried to repair you car on -20C?), so I'd like to have a prepaired 2 speed fan working for replacement when I remove bumper, panel, etc. Just in case, you know.

Thanks!

[T-Cut]

I don't know if it will help with identifying the 2-speed relay, but I'd suggest you read this, noting the info given in Post 5: http://www.the75andztclub.co.uk/foru...ead.php?t=1371

TC

[Fraser Mitchell]

A member here also got some replacement motor brushes for the 3-speeders, but the motor is difficult to strip as there are securing lugs to be unbent, and then rebent to get to the motor brushes.

However, I understand the -20C difficulty !!

[Dronix]

Thanks, T-Cut, somehow I missed this post. That helps a bit, but not much - as you can see there, half of electric connections is on PCB board, and it shot just from one side, so I still can't get how does 1st speed works - does resistor have parallel or serial connection? Does resistor using during 2nd speed work as a parallal or not?
Does anyone have Rave installed, could you check does Rave have electric schematic of 2 speed fan?

Thanks!

[SD1too]

Originally Posted by Dronix

Does anyone have Rave installed, could you check does Rave have electric schematic of 2 speed fan?

Andrew,

RAVE will not help you. The wiring diagram for the original factory 2 speed fan (not fitted to KV6 models) is extremely misleading. It shows two motors and no resistor.

... I still can't get how does 1st speed works - does resistor have parallel or serial connection? Does resistor using during 2nd speed work as a parallal or not?

On the 2 speed system, I understand that the first speed is achieved with the resistor wired in series [note: not 'serial', that's something entirely different] with the motor. For the second faster speed the resistor is out of circuit, the motor receiving the full supply voltage.

But Andrew, a word of warning. In your first post you said that your existing 3 speed fan is "dead". Are you absolutely sure? Testing this system is not straightforward. Bearing in mind the weather conditions in Moscow, have you used the instrument pack diagnostics to check operation of your fan's slow speed? If not, what makes you think it's "dead"?

With fan questions, it's useful to know the year of your car, whether it has ATC air conditioning, automatic transmission, and whether it's had a fan motor replacement or modification earlier in it's life.

Simon.

[T-Cut]

I believe the two relays open one or other earth return. One earth circuit with the resistor and one without. The motor has a permanent 12 volt supply, so it's the way it is earthed which selects the speed.

TC

[Dronix]

Originally Posted by SD1too

Andrew,
On the 2 speed system, I understand that the first speed is achieved with the resistor wired in series [note: not 'serial', that's something entirely different] with the motor. For the second faster speed the resistor is out of circuit, the motor receiving the full supply voltage.

Yes, thanks, english is not my native language, so I get it right just don't know how to say it correctly

But Andrew, a word of warning. In your first post you said that your existing 3 speed fan is "dead". Are you absolutely sure? Testing this system is not straightforward. Bearing in mind the weather conditions in Moscow, have you used the instrument pack diagnostics to check operation of your fan's slow speed? If not, what makes you think it's "dead"?

I disconnect fan connectors, and put +12 & GND on a power wires, and then +12 step by step on speed realys feeds. And it doesn't spin (it was earlier on the same test).

With fan questions, it's useful to know the year of your car, whether it has ATC air conditioning, automatic transmission, and whether it's had a fan motor replacement or modification earlier in it's life.

2000, wit climate, MT. Fan has been changed twice at least (preivous owner and me, when I got my car crashed.). So, I have my previous 2 speed fan (used before crash), and after crash I installed 3 speed fan. In that car crash relay box was destroyed and some wires cut off, but motor (2 speed) is running fine.

[Jules]

Be very careful when rewiring.

Old 3 speed control boxes switch the +12 volts to the relays, where as the later 2 speed Boxes switch the earth (NEG) side through the relays.

It is possible to connect a 3 speed control box into a single speed motor with the resistor in series with small middle relay.

Purple circuit (other small relay becomes redundant)
The Large relay becomes the HIGH speed relay. (was the lOW speed in 3 speed configuration)

There's 5/6 wires to change/join all together
(made some exact notes somewhere but can't find them, as for us it's far quicker and less time consuming just to fit a Kenlowe!)

Good luck

[SD1too]

Originally Posted by Dronix

Yes, thanks, English is not my native language...

Well you fooled me!

I disconnect fan connectors, and put +12 & GND on a power wires, and then +12 step by step on speed relays feeds. And it doesn't spin...

Ah hah! The car's ECM does not switch the positive feed to the relay coils, it switches the earth side. The car will provide +12v IGN to the yellow wire which supplies all three relay coils. All you have to do is earth the coils one by one. The slow speed is the blue wire, medium speed is blue/yellow and fast speed is blue/red.
I'm assuming that your 3 speed fan is wired via an unmodified relay box in working order.

Originally Posted by Jules

Old 3 speed control boxes switch the +12 volts to the relays, where as the later 2 speed Boxes switch the earth (NEG) side through the relays.

Jules,

My car is 1999 which I think qualifies it as 'old'. Mine is wired so that the earth side of the relay coils are switched by the ECM.

Simon.

[Jules]

Lets not get confused here.
My statement earlier was the OUTPUT contact side of the relays!

The primary COIL side has always been wired the same for early and late cars, otherwise the later type control boxes wouldn't be backward compatible if you think about it.