View Full Version : DIY: Cooling Fan Relay (Repair/replacement)

09-14-2011, 11:24 AM

My area had a lot of rain which lead to extensive flooding last week. My girlfriend has a 2006 A4 2.0TQ 6MT with some extras. Around 10:30pm Thursday we were evacuating my house to a safer area and she hit standing water. [headbang] The car was fine or so it seemed. She told me she hit a puddle, but later I found out it was pretty deep standing water. Her car seemed to be running fine so I said don't worry about it.

Friday afternoon she calls me at work and says her car is making a "blowing air sound" even though the car is off and has been since the night before. Her coolng fans were running and they wouldn't shut off until the battery was dead. After work, I went over to jump start it and as soon as I connected the jumpers the cooling fans turned on again and the car was off. I started the car and everything seemed fine. She drove it home and I jumped on the great world wide web and searched for "B7 A4 cooling fans on with car off." I found mostly info for B6's. It usually is the 219 relay under the ECU cover. I think the 219 relay is now the 614 relay on B7's. I figured since B6's and B7's are very similar I would start there. The other culprit is usually the module behind the drivers headlight that connects to the fans. Replacement DIY here: http://www.audiforum.ca/showthread.php?t=1017


Do this at your own risk. I thought it was pretty easy but I'm not responsible if you screw things up. This is not the only way to do this, it is how I did it.


Park your car and set the ebrake
Pop the hood and remove the battery cover
Disconnect the negative battery terminal
Remove the rain tray
Remove the drivers side wiper by prying off the plastic cap and then removing the 17mm nut
Remove the cowl clip on the drivers side. It can be seen here:


Once removed you can pull the cowl up like this:


This will allow you to access the back right screw through the wiper hole. The screw can be seen here:


My screw is a philips but yours should be a t30 torx. There are 5 total. 3 in the front and one at each back corner.

The back left access can be seen here:


The front 3:


After you remove all 5 screws you can remove the ECU cover like this:


At this point you probably will have to follow the ECU removal here: http://www.vaglinks.com/Docs/Audi/B7/AudiZine.com_Audi_A4_B7_ECU_Removal_DIY.pdf
It's for RHD but it's all the same.

After you free the ECU you can pull it out of the way and you will see this:


Another shot:


I could see water in the ECU box but had already removed it at the point of this picture.

I believe the middle relay is the cooling fan relay. The whole relay/harness holder can be lifted up to remove it from the ECU box as shown here:


After you remove the relays you can remove the harnesses if you wish to make cleaning them easier. You will see the two locking tabs that hold them in place.

This shows the relays removed and in the correct orientation:


I opened each relay up by prying the locking tabs open with a small flat blade screwdriver.

Here is an open one:


Here is the nasty one:




Here is what I used to clean them with:


I sanded the terminals down and then sprayed them with electrical contact cleaner. I also sprayed the relay side. Wear gloves with this stuff, it starts to burn your skin.

After I finished the relays I removed the water in the bottom of the ECU box with some paper towels. Then I carefully sprayed some cleaner into the wiring harnesses. Make sure you do not get it on your paint or windshield. It might cause problems. I used a rag to hold the harness and collect overspray/drips while I sprayed them.

This shows the dry ECU box:


Once everything is clean and dry reassemble in the reverse order and start it up and make sure everything is good. This fixed her problem. No more random cooling fans with the engine off and no more dead battery consequently. [:)] It has been a few days now so I feel confident that the problem is gone. I had to do this same fix on my washing machine since I ended up with water in my basement from the rain/flooding. It worked for the motor control unit circuit board! [:)]

11-24-2011, 11:20 PM
Thanks for the write-up [up]

06-10-2014, 10:16 PM
My cooling fans are both not working either which has made my A/c not work either... where can you buy this relays? and did your A/C stop working ass well before changing the relays?

06-21-2014, 05:20 PM

R Nasty
12-26-2015, 03:53 PM
Awesome thread!! Had this exact same issue...Google it and found this thanks a bunch. Car is back to normal no more dead batteries