So we had some really heavy rains here recently and just under a week ago, my daughter went out to find the A4 wouldn't start. She had left the GPS on so had a word about that, recharged the battery, got it checked and then moved on. But then the fan came on when she was putting the top down. Didn't think much of it as it went off. Then a couple of days later, she came home and it was sitting there whirring its fan until she tried to use it and it wouldn't start. So another recharge and she was going again but now it is running whenever the car is off.

Symptoms are, when the battery is connected, after about 10 seconds, the fan comes on. If the door is opened, the fan stops but starts again until the door is closed or starts again anyway after about 30 seconds. If the ignition is switched to "on", the fan stops and doesn't come back on while the ignition remains on. Once the ignition is off, the fan comes on again after about 30 seconds. Pulling fuse 4 stops the fan coming on.

From reading around this and other forums, the finger seems to point squarely at relay 219. I have done a partial inspection of the ECM box and it appears to be in reasonable shape but the inside of the car did have some dampness after the rain. I don't want to pull things further apart (removing wipers, cover etc) as I don't have the relay to hand at the moment and I'd like to get it done in one go since removing the wiper cowl will make the compartment more susceptible to water intrusion and we might have more rain coming in. So what I'm hoping for is if someone can say "No it can't be relay 219 because 'X' from what you described" and I can look somewhere else otherwise.

Thanks in advance.

 

Additional info: Just did a scan and no fault codes.

 

I'm experiencing the exact same symptoms as you were. Did you get this fixed? What was the root cause? Was it the relay? I'm positive whatever solution you had will work for me as well. Is this forum still alive?

 

If your fan randomly comes on it's the fan relay. Mine did the same and I took the ecm out and you could see the water line had almost covered the fan relay. Took the relay apart and it was nothing but rust inside. Mine the ECM cover was broken allowing water inside the box where the relays are. I also drilled a hole in the bottom of the box to allow any water to drain. Also check the area where the battery is. The cover is missing allowing all kinds of tree debris to fall in that area and the 2 drains plug up. Mine at one time had about 3 inches of water under the battery and if left like that water can seep into the car.