We had some pretty heavy rain the other day in MA and my wife drove through a knee deep pool of water. When she came home and turned the car off, the fans came on a moderate speed about 15 minutes later, stayed on for a few minutes and then shut off. Shortly thereafter, they came on for 5 to 10 seconds and turned off. They continued to do that for awhile. Finally I went out and turned the key to the on position (never starting it) and it stopped it. I turned the car back off and went inside. About 20 minutes later it started doing it again. I can't seem to get it to stop. I'm considering pulling a fuse before it drains the battery. I stress that the car is OFF and no key is in the ignition. This has never happened before. Could it be that there is moisture in the fan switch that is causing some kind of short?

KJ

 

Update: Took the car to my mechanic and he could really find nothing wrong. Still happening with more occurrence now. Taking it to the (gulp) stealership to see what they come up with. I'm surprised no one has any relevant comments? I'm going with replacement of the lower fan switch as I think it was somehow damaged by the water.

 

The other item that is a culprit is water in the ECU due to clogged drains. Lots of threads on that subject.

 

Holy cow, Lyleswk! Sure enough, went to Audizine and there was the EXACT SAME issue I was having with my car except on an '06 Avant. ECU unit gets crack in housing or torrential rain causes some water to get in there and bam! Fans on when the car is off. So check this out. The dealership (Bernardi Audi) has my car all day from 8:30 and doesn't call me until after 6 to tell me that they need to do "further diagnosis" in the morning. The service advisor can't even give me a clue as to what's wrong. So I tell him I'm going to have to pick the car up because I need it to actually live my life the next day. I get there and after awhile of joking about the lady who just left who was haggling over the charge of shop materials and hazardous waste disposal (she said she could get rid of it herself because the town of Wellesley will take anything - if you don't know Wellesley, VERY wealthy, but the wealthier you are, the cheaper you are, I'm generalizing of course, AND she got Audi to replace her thermostat free out of warranty!), he says "well, to be honest, we've been really busy and the guy who was supposed to work on it kept getting pulled away and didn't have a chance to diagnose it." So in the meantime, the "I'll dispose of that hazardous waste myself" lady has dropped off her loaner car and he says he can give it to me if I want to do that instead. I say sure ('13 A4 2.0 with just over 2K on it) and off I go. So today he calls me at 11:30 and says "the mechanic heard the fans come on and he pulled the code and it looks like the fan control module." He quotes me almost $1,100 (which includes the $125 for the diagnostic work I agreed to pay) and (it's 11:30 AM) he won't be able to get the part until tomorrow. I tell him I'll think about it, but it sounds way expensive because I don't think the part is more than $400. He calls me back 30 minutes later and says "I can get that down to $850 for you." Really? Like he's doing me a HUGE favor?! But he's got to know by 3 PM because he can get the part ordered. This is now (on their web site) the "largest Audi facility in North America" that they just finished buiildiing and is 66,000 square feet and they don't carry this part?? So I call ECS (love them!) and they quite me $316 for the part delivered. I'm in the ballpark even if they mark it up to $400. Then I look up the install and it doesn't seem like it would take a "master mechanic" more than 30 minutes to do the job. I also find out about the ECU (ECM) being an issue and call the service advisor back to tell him all of this, which results in a conference call with the mechanic saying he was going to check the ECM first just in case, but that would constitute time on the clock and if that's not the issue then they'd have to charge me and then go replace the fan control module anyway. I tell him that seems more plausable than the fan control module because of where it sits and he says "the ECM sits up high, too" and I say, "yes, except when torrential rain comes down the windshield and splashes the ECU box over the cowl (which is a known problem), it seems more reasonable to me to check that first and that I'd feel better taking it back to my mechanic.

 

Then the service advisor says "with all due respect, your mechanic couldn't fix the issue" and I say "but you guys aren't really sure either and it's going to cost me more time and money to find out." So we agree to disagree and I'm picking the car up, will continue to pull the fan fuse so they don't run when the car is off, and check the ECU. Anyone have a link for that? I'll look around as you suggested Lyleswk, but just another in a long line of entertaining and annoying stealership anecdotes. Will update again soon.

 

What did they say about the ECU being wet? I might even pull the ECU and put it by a dehumidifier for a few hours to see if you can pull out any moisture that may have gotten in.

I might even go as far as putting it in a bowl of rice (works for smartphones that have been submerged in water why wouldn't it work for an ECU)

Jason

 

Well, I believe lyleswk is absolutely correct. Check out these photos!
https://www.audiworld.com/forums/alb...albumid=169089
I've written up a lot in the pictures themselves, so I won't take up more space here. Suffice to say, the relay (219) is pretty orange - just like lyleswk said it would probably be. The other two relays looked pretty decent, so I didn't replace them.
Thanks for the post, Jason at ECS. The ECU was not damaged and the water that was in the box was 3-4 inches below the ECU (see photos of the remnants of the water in the box).
My ECU (or ECM, whichever - the dealership mechanic called it the ECM) box has a crack in the back left corner. Not the cover, but the box that that everything lives in. Any thoughts about either rigging a repair of the box or replacing it? I basically see that it is attached at three points, but with all the wiring running in there, is it difficult to replace?
KJ

 

I also am thinking of complaining to my contact at AoA (she got my heated seat module replaced for free a few years ago!) about what I consider the unethical practices of my local dealership. I don't have it all back together, but they wanted to replace my fan control module for $1,100 which included $125 of diagnostic work. When I had my conference call with the service agent and the mechanic and suggested they look at the ECU first, they were reluctant to do it and I think if they had, they would have nailed me for all of the relays, which they were charging A LOT more for compared to other dealerships, the broken ECU box, the windshield cowl, and then they probably would have installed the fan control module anyway. Would it be a waste of time to describe all of this to AoA?
KJ

 

Theres the cooling fan relay in that ECU box. I have seen this exact thing several times. Its annoying people break the boxes when diagnosing somthing, then just dont say anything. The cooling fan relay i have found gets submerged, its at the bottom on its side, and then the contacts inside corrode and it sticks on and makes the fans run forever. Replace the relay, dry everything out, fix the broken plenum box. usually you can just dry the ECU out if its not corroded all the hell inside. Wish i saw this thread in the beginning. might have been able to help before somebody just threw everything in the box at you.


The box itself is easy to replace. The connectors are all easy they just pull right out, just give a quick pull they come right out. the nuts holding it, pry it up, it might be glued down. Make sure to clean and reseal the new one down with silicone or something if thats how it comes out.

 

Thanks, Prospeeder. For right now, I made a replacement piece for the box with some Locktite putty. It's crude, but I think it will keep water out. Yeah, I wish you had seen it, too! Turns out that the housing has the cracked back left corner, the cowl had a chunk cracked off which was still in there by the wiper transmission (I glued that back on), and the left side retainer for the ECM was broken (8E1 907 354). I'll have to call around for that tomorrow. Really? You make it sound like the housing isn't difficult to replace? I see what you describe. I see 4 wiring harnesses that snap in going into the car behind the ECM and I see that the relay housings just clip in, but I'm concerned about the wiring to the ECM. Not sure how that unhooks. Can anyone talk me through that? I can see getting out the housing easily, but it's the wiring that worries me.
KJ