Hi all,

This morning I had an issue with the car where it wouldn’t start, and when keys were in the ignition it came up on the MFD with an airbag fault and lots of beeps.

Decided to get the AA out who took a look at the battery and it was almost flat. At the same time as this was being done, the keys of the car where in my pocket and the coolant fan was running at low speed intermittently. The AA guy guessed this is what has run the battery down.

We placed a booster on the battery of charge it and all of a sudden the coolant fans started up to full speed, and only stopped after the engine was switched on an off again.

Battery was accepting and holding a charge fine, so let it run for 20 mins to make sure it was fully charged before coming to work.

Arrived at work at 11.30 parked up and left the car in the carpark.

Went to lunch at 12.30 and thought I will try and start the car again.

When walking up the car the first thing I heard were the coolant fans turning.

Tried to start it and got nothing apart from a continuous click. It seems there was just enough charge left to kick the starter motor, but not enough to start the engine.

The only error that came up was an emissions error, which the AA cleared.

Does anyone have any idea what could be causing these fans to continuously run hours after the car is switched off?

Many thanks in advance,

Ross

Anyone please?

Have you scanned the car for sensor faults? Do the sensors read correct temps?

Could be a faulty temp sensor sending the fans to full.

Sensors will tell you the temp on scanning tools (VCDS etc) so for a cold engine the temp of coolant should be around ambient temp.

I know if I unplug the coolant sensor on my 2.0 PD the fans spin up to full speed.

Fail safe design etc.

Edited 19 October, 201213 yr by Plantman

The AA scanned the car and showed me all the different readings on the screen.

Temp sensor was reading correctly, he said there wasnt anything strange sticking out to him.

The fans are controlled by a relay, and have been known to have issues before with the fans running fulltime.

The fans are controlled by a relay, and have been known to have issues before with the fans running fulltime.

So its a possible new relay thats required for it?

I've seen this a couple of times and both times the cause has been water deep within the layers of the fusebox. Fusebox removal, dismantling and drying out fixed it.

Could this also be the cause of no fans at all ??