Radiator fans full speed

[submarinedog]

Hi all,

Since yesterday after work, my radiator fans have been operating at full speed - even from a cold start. I have checked both fans on the radiator, and they are spinning at full speed.

I've also noticed on my MFA that the ambient temp reader it began at 29c on a cold start, then had reached 34c by the time I arrived home (5.30pm). The max temp in Brisbane today was 30c.

I am thinking it could be a faulty sensor.. but not sure which one. Coolant temps are fine, it's around 84c and the car drives perfectly normal.

Does anyone have any ideas? I'm thinking if both radiator fans are spinning then they're not at fault..

[brad]

Sounds like the sensor. They fault to closed so that you can still use the car.

[submarinedog]

Thanks for the reply Brad.

What do you mean they fault to closed?

[brad]

Most vehicles with electric fans will have a temperature controlled switch. Generally, if the swith fails, it will default to the closed circuit position so that the fans are permanently on regardless of engine temperature, thus you can keep driving the car without overheating & damage.

It should be an easy fix for any mech with VW knowledge.

[Transporter]

Is that with the air/con OFF or ON?

[submarinedog]

Brad - thanks for the explanation. I drove the car out to work this morning and it seems to have gone back to normal. I hope it stays this way, but will keep an eye out if it happens again. Fingers crossed.

Transporter - it happens when both AC is either on or off. Also changing the different mode settings to auto/Econ doesn't seem to have any effect either.

I will see how it goes over the next week or so and will keep you guys updated!

[submarinedog]

Hi all,

Just an update on this. As I suspected, it turned out the ambient sensor located near the radiator/intercooler behind the front bumper was playing up. Had a forum member check this for me and confirmed it was the sensor (many thanks).

Since then however, the fans have been operating normally, and the car drives like she always does.

I believe a replacement of the sensor will rid of the issue completely, however, I will be leaving it for the time being as things seem fine.

Thanks all for the help!