Been trying to come to reason with my audi tt. Got hot on me after I left it running while I went into a friends shop for 5 min. Realized the fans did not come on. Found that the fan control module was bad, replaced, still nothing, can any one tell me if there is another device that controls fan on like a fan sensor or fan control device that operates from temp?

 

Boost Controller is another device for controlling the fan's activity.

 

where can I find it ? and what is the boost controller ?

 

Another thing you can do if that doesn't work is go through all your fuses and inspect them. You might find 1 or 2 that were blown. If it still doesn't work, check that the wiring to the fan isn't cut somewhere.