Radiator fan not working

[Copilot]

So it all started with my AirCon not working.

Mine is a '01 R75 KV6
I went to the shop to check it. After the compression test, I figured out that there was just 240g of R134a. I decided to recharge it.
The service was done, but still no aircon.

Then I checked here in the forum and saw that I also needed to check if the radiator fan was working.
Well, it wasn't.

So I decided to do the Radiator fan speed test (Thanks for the great post Jules)

Results:

• Set the Aircon to the DEMIST function. No slow speed at all.
• Yellow/Grey & black wires shorted with a paperclip the HIGH speed does not kick in

I have also checked the fuse in the engine compartment just in case.
My fan is a 4 Wire – 3 Speed fan with no resistor.

My questions are:
Have I tested as much as needed to identify the problem?
Could the problem be in the brushes?

Thanks for any advice.


Here is a pic of the fan connector box.

[Arctic]

Hi Pedro
You have done the checks that was required and from your results I would most certainly say that the brushed have failed, to what extent you will not know until you remove the fan from the car.

Once the fan is off the car you can then open up the fan motor by removing the lid this will reveal how bad the brushes have failed also if the commutator is still in a reasonable condition for you to bother changing the brushed or not.

If they are to bad or you do not want to repair the fan if it can be, then contact Jules about a Revotec fan link below

https://the75andztclub.co.uk/forum/s...d.php?t=189409

[vitesse]

You might like to consider this supplier https://www.old-germany.de/ecommerce...g2s1smq9p6pq86

It’s unlikely that you will need more than 2 brushes, and their postal rates within Europe are much cheaper than the UK based company most forum users buy from. I’ve managed to bring back to life several fan motors, but in one case commutator wear was too much.

Their brushes are slightly oversized so will need some trimming to slide easily in / out of the holders.

Regards

[SD1too]

Originally Posted by Copilot;

Yellow/Grey & black wires shorted with a paperclip the HIGH speed does not kick in ....
My fan is a 4 Wire – 3 Speed fan with no resistor.

Pedro; just for your information, on your 3 speed system it was the MEDIUM speed which did not work when you bridged the trinary switch. This evidence suggests that the earth brush common to the low and medium speeds has worn excessively. There’s a good chance that your motor will be repairable and as you are technically competent, I recommend that you do that.

The most reliable place from which to buy your new brushes is Engineering Carbon Products Ltd. in Croydon, England. In conjunction with club member Greeners and myself, this company produces its brushes to the same or a better specification than the Siemens originals. This is because they were supplied with a sample to use as a template. They will not need to be trimmed (the size is 4.6 x 9.65 x 23 mm) and the faces are shaped to match the commutator contours. I suggest that an extra bit of postage cost is money well spent! It’s your decision of course, but some members have complained about early failure after fitting brushes bought from e-bay. There have been no complaints about ECP’s brushes. Mine have been in service for nine years and over 40,000 miles.

Simon

[vitesse]

Simon,

“the most reliable place” are you suggesting that the German ones are less than reliable? Have you tried them yourself and concluded they are less than reliable?

I’ve only used them for six years but my fan motor is still working and so are the many other motors I've repaired (to the best of my knowledge) so I’m not sure about your wording. You also say that there have been no complaints about ECP’s brushes, is this insider information? I could not possibly same the same about the German ones as I simply don’t know.

What I do know is that ECP’s European postage rates are high, unreasonably high and I have no wish to place business with a company that I find unreasonable. I’m quite prepared to spend a few minutes trimming the German brushes rather than sponsor ECP.

The German source will sell individual brushes and the buyer can get the two he no doubt needs. ECP on the other hand seem only so sell sets of four with no option to buy less. I’ve never seen a fan motor that required a change of all four brushes, have you?

Mike

[SD1too]

Mike,

You recommended your German company’s product and I recommended ECP’s. We are both happy with the decisions we made. As a result we have helped the OP to have a choice.

I am not impressed with any company which sells a product which, in order to use, I then have to modify, but that’s just my personal opinion and I note that you don’t agree.

I didn’t suggest that the German product was unreliable; I referred to e-bay.

No, I haven’t seen a motor requiring all four brushes to be replaced. However not all club members follow our philosophy Mike of replacing only what is necessary. Also many people buy their new parts before dismantling and so will not know how many brushes they will need. In that case they will most likely want four.

Best wishes,

Simon

[Copilot]

Originally Posted by Arctic

Hi Pedro
You have done the checks that was required and from your results I would most certainly say that the brushed have failed, to what extent you will not know until you remove the fan from the car.

Once the fan is off the car you can then open up the fan motor by removing the lid this will reveal how bad the brushes have failed also if the commutator is still in a reasonable condition for you to bother changing the brushed or not.

If they are to bad or you do not want to repair the fan if it can be, then contact Jules about a Revotec fan link below

https://the75andztclub.co.uk/forum/s...d.php?t=189409

Hello Artic

First, let me thank you for your advice and also for your videos on Youtube regarding the Fan testing, They are very helpful.

I also believe the problem can be the brushes. But if the commutator is in bad condition? Is it possible to repair it?

EDIT: The fan does not work in any circumstances. I forgot to mention that I did this test as well.

Originally Posted by SD1too

Pedro; just for your information, on your 3 speed system it was the MEDIUM speed which did not work when you bridged the trinary switch. This evidence suggests that the earth brush common to the low and medium speeds has worn excessively. There’s a good chance that your motor will be repairable and as you are technically competent, I recommend that you do that. (...)

Simon thank you for your advice. Yes I should mention "MEDIUM speed" instead.

I really want to fix the Radiator fan. I don't feel confident to drive around without one.

Also, does the AirCon depends on the Radiator Fan to work?

Vitesse thank you for your suggestion as well

[vitesse]

The commutator is not repairable. But I’d say that you’ve got a good chance, perhaps 6 to 1 that your motor is repairable, at least that’s my experience.

Normally ACC is dependant on the fan, but some people have told me that they have cold air when driving at speed. My AC didn’t work at all when my fan stopped working.

Repairing the unit isn’t that difficult if you are used to taking things to bits, the most difficult thing is getting the motor out. Artic has posted lots on this subject, others too.

Regards

[Copilot]

Originally Posted by vitesse

(...) the most difficult thing is getting the motor out. (...)
Regards

Well, that was the easy part, to be honest,

I can't remove the fan motor lid. Or the lid clips are too rusty or I should really consider going back to the gym...

Am I doing it correctly? Should I use another tool to open it?

[Arctic]

Originally Posted by Copilot

Well, that was the easy part, to be honest,

I can't remove the fan motor lid. Or the lid clips are too rusty or I should really consider going back to the gym...

Am I doing it correctly? Should I use another tool to open it?

Hi Pedro
Try this below

https://youtu.be/ls1BJGxUoPo