Anyone heard of this...WTF

[Euroxtc]

Had to jump the battery and realized that both my fans are turning on whenever it feels like it. I dont have to drive it or have the key in the ignition. Its killing my battery so I'm gonna drop it off at the shop this week. Anyone heard of this happening before? Maybe a bad relay switch or something.
Its a 2003 A4 3.0

[quattro16]

Fan control module or water has gotten into the ecu box shorting out the relays below the ecu....

[waldo1324]

i vote for green coolant temp sensor. my fans were kicking on upon startup in the winter and whenever else they felt like it.
go ahead and replace the bottom sensor as well if yo uare draiinig coolant

[onceover]

Water in ECU box.

[widgget]

yup, water in the ecu box, been there done that.....

if you are lucky you can take the 219 relay apart and clean it out. the spring rusted out do to the water on mine so the contacts were not being pulled back, cleaned it out, stretched the spring a little and made a new hook on the end, reassembled and it's been working for more then 2 years now.

[Euroxtc]

[Ok Thanks . Where is the boxQUOTE=widgget;7677224]yup, water in the ecu box, been there done that.....

if you are lucky you can take the 219 relay apart and clean it out. the spring rusted out do to the water on mine so the contacts were not being pulled back, cleaned it out, stretched the spring a little and made a new hook on the end, reassembled and it's been working for more then 2 years now.[/QUOTE]

[Snow White]

Fan control module or water has gotten into the ecu box shorting out the relays below the ecu....

Agreed with the masses- water in your ecu box.

Had the same exact thing happen to my car, took it into the shop twice and they couldnt find anything. Replaced a bunch of crap (including the battery, alternator, etc) at the cost of about $600 in total and nothing helped. Then found water had gotten into my ECU box (because of a shitty alarm install), causing the relays to short out. $40 later for a new relay and it solved the problem instantly (not sure if that was the exact price)



Try to check the ecu box first before taking it to a shop. You'll save yourself a lot of time, money and headaches.

[EinSchnellAudi]

Another vote for water in the ecu. Do not know why it seemed start when you jumped the battery, unless it had killed your battery because it had been doing it previously.

[Gmoney]

same experience here a few years back. Water in the ecu box was the culprit. I took the ecu out to send it to APR and didn't properly seat the lid back on.

[Euroxtc]

Is this the box under the glovebox?

[travrach]

It under cowl, by brake booster, sorry pic not the best

[onceover]

ECU removal instructions

http://www.goapr.com/support/ecu_a4_b6.pdf

[JolePatrol]

I too had this problem with water being in the ECU box. I think the OP said that the fans drained the battery in the first place which is why he had to jump it.