Fans aren't turning off

[Bug_racer]

There is a sensor on the radiator which has 3 wires . One is supply the other 2 send signals back to the fan ecu . You can start there , the 3 sensors in the thermostat housing I think only 1 has the power to activate the fan when it reaches 120 or so and it activates the super high speed fan .

[stefcio007]

There is a sensor on the radiator which has 3 wires . One is supply the other 2 send signals back to the fan ecu . You can start there , the 3 sensors in the thermostat housing I think only 1 has the power to activate the fan when it reaches 120 or so and it activates the super high speed fan .

Is that the one under the silver cyclinder canister thingy? I unplugged it and nothing changed if that helps.

[Bug_racer]

Its screwed into the radiator , its just above the lower coolant hose

[stefcio007]

I've got it, but not sure if taking it out will cause coolant to leak out.
Would the blown fuse have anything to do with it?
Which sensor should I replace first? And where can I get one.

[dylan8]

mine did odd things like this also.
Solved mine by tidying wiring and replacing just about every sensor in that department.
Sorry, cant be of more help

[Bug_racer]

I've got it, but not sure if taking it out will cause coolant to leak out.
Would the blown fuse have anything to do with it?
Which sensor should I replace first? And where can I get one.

Don't pull it out just check to see if there is power coming out of the switch

[stefcio007]

So, coolant is actually leaking from the sensor area, just booked it in to get it all sorted as I don't have time to do it all myself.

[The_Hawk]

Exploratory fixing on a car... that's not going to end well. I'd suggest they will remove the sensor, fix the leak and after that it's anyones guess.


To test a sensor you can either read it with a computer or a multimeter to see if it's reading correctly (and changing it's reading) as expected.

In this case, one of the other options is to plug in a spare (and known good) sensor and see what happens. Since the new sensor should be reading ambient temp the fans shouldn't come on. If they do, the problem is somewhere else.

Finding a random electrical problem is a bloody nightmare. It's a toss up between a good VAG specialist and an auto electrician who knowns VAG and it's likely to be long and expensive unless you get really lucky.

[stefcio007]

So, I was having a chat with my dad about buying a new Ford. And wouldn't you know it, the fans all work perfectly normal now!
I verified this a few times, just to be sure.
Going to buy new seals though to make sure I stop leaking, even though it's very minor.
here's hoping the issue doesn't re-appear.

[The_Hawk]

Have to wonder if it was loose wiring on one of the sensor causing the issue and all the fiddling as fixed them up!