16v Radiator Fan stays on constantly!

[Fat Audi 80]

Hey Guys,

Please could you give me some advice on the following problem on my 1990 16v:

The radiator fan kicks in and runs fine but will not switch off, even when the engine gets cold (ignition off and in afterrun state). It now flattens the battery! 

I have now taken to removing the fan fuse if the fan is running when I switch off the car.

As I understand it from the Haynes book of lies, there is no relay on the 16v radiator fan circuit but there is an afterun circuit located between injector 1 and 2. I cannot find this circuit, but suspect it is the culprit.

Anyone else suffered this or can provide any advice.

Many thanks,

Steve.

[Mr Blue]

there is a fan switch that is located at the right hand side of the rad (looking into the engine bay) at the bottom

It has a connector plug attached. Change this switch.

You get 2 pin and 3 pin switches so buy the right one

[Fat Audi 80]

Hi Thanks.

I am fairly sure is not that switch causing this problem. I have already replaced it.  Even when that switch is cold again (Open circuit) the fan still runs. I am fairly sure there is another arrangement for the after run that is playing up. (I stand to be corrected however)

Cheers,

steve

[Uruk Hai]

So when the fan is running it stays going even if you take the plug off the fan switch 

[Fat Audi 80]

So when the fan is running it stays going even if you take the plug off the fan switch 

No, it will switch off. But, when the ignition is OFF and has cooled again, after half an hour, the fan is still runnning. In the morning, he fan stays off  as normal until hot and will also switch off again with the engine running. If the Ignition is OFF and the engine is warm the fan runs forever!

I hope that explains it.

The Haynes manual states there is an afterrun circuit, does anyone know what that is or where it is???

Cheers,

Steve.

[DarnPB]

When it happens again, disconnect the black water sensor lead and see if it stops. That sensor may have closed circuited.

[Fat Audi 80]

When it happens again, disconnect the black water sensor lead and see if it stops. That sensor may have closed circuited.

Where is that located please?

Many thanks,

Steve.

[DarnPB]

In the pipe from the head to the rad.

[herbster]

Rubjonny pointed out to me that there is a rad fan cut off switch mounted like an air temp sender above the inlet manifold with a single wire going to it, it bolts on just below the rocker cover, this is on - mine a 8v k-jet, if you got the one it could be the problem? 
good luck

[clipperjay]

Rubjonny pointed out to me that there is a rad fan cut off switch mounted like an air temp sender above the inlet manifold with a single wire going to it, it bolts on just below the rocker cover, this is on - mine a 8v k-jet, if you got the one it could be the problem? 
good luck

yep near the FRP its a plug unplug it and see what happens its a overheating overrun sometimes the wires break and causes open circuit!