Audi s3 engine fan issue

[gtronroids]

Quick question and it is a weird one. My fans are not coming on in the s3. I can jump the pins and the fan works but if everything is plugged in like it should be the fan doesn't come on. I have replaced my thermo fan switch, fan control module and have got a new thermostat to put in but thought I would chat with you all before I put it in. All the fuses are good but here is the weird part, if I pull fuse 16 in the side fuse holder the fan comes on regardless if the car is on or off. Put the fuse back in and the fan goes off, wtf.... Any thoughts, is there another relay or fuse that I don't know about? Another theory I have is that the thermostat is not opening and not allowing the coolant to pass over the thermo fan switch but everything comes back to why does the fan come on with the #16 fuse pulled out


Sent from my iPad using Tapatalk

[Umai Naa!!]

Is this a Mk4 Golf era S3?

Could be the fuse box on top of the battery.

[gtronroids]

Checked all that and all good. it is a Audi s3


Sent from my iPad using Tapatalk

[AdamD]

Checked all that and all good. it is a Audi s3

We know it's an S3. Which generation of S3? 8L, 8P or 8V?

[gtronroids]

Sorry 8l I now know why the fan comes on if the #16 fuse is pulled. Pulse Width Modulation.


Sent from my iPad using Tapatalk

[Jenno007]

I have the exact same problem.

Today I replaced both fans and the fan control unit and now they don't work at all! Not even with the A/C on!

However, if I pull fuse 16 they both come on.

I would really appreciate if anyone had a solution

[Umai Naa!!]

As per above, which generation A3/S3?

[gtronroids]

I know why they come on when the fuse is pulled. Pulse width modulation. So this is normal. However I swear there has to be another relay/fuse hidden somewhere other than the fuse block in the door and the fuses atop the battery.


Sent from my iPad using Tapatalk

[gtronroids]

If you are really desperate you can run a toggle to fuse 16.


Sent from my iPad using Tapatalk

[Jenno007]

I want to fix the issue, and I have another daily so I don't need a 'makeshift' fix

I'm thinking it's the fan control module, I've purchased a new one to see if the new one I have is faulty.

Audi S3 8L

[Umai Naa!!]

I'd still look at the fuse box on the top of the battery as well.

It's known to fail internally, and cause all sorts of electrical problems, some relating to the fans.

[gtronroids]

Hi Umai, I have probed and removed all of those fuses and they all tested fine. Do you know if there is another relay other than the fan control module under the battery?


Sent from my iPad using Tapatalk

[Jenno007]

the fact that the fans come on with fuse 16 removed would to me mean that it cannot be the fuses on top of the battery?

if the fuses on top of the battery were gone I would imagine the fans wouldn't work full stop?

But I did have a good look at the fuses on top of the battery and nothing seemed wrong to me.

[gtronroids]

Jenno, have you jumped pin 1 and 2 on the thermo fan switch (the one on the side of the radiator)


Sent from my iPad using Tapatalk

[Jenno007]

Jenno, have you jumped pin 1 and 2 on the thermo fan switch (the one on the side of the radiator)


Sent from my iPad using Tapatalk

Nope havent done that, by jump do you mean run 12v direct to it?

I would of thought the fans would still come on with the AC though if it was the thermo fan switch?

Thanks for the suggestion though I'll try it tomorrow!