OK, Ive been trying to diagnose the problem causing my a6 2.7t to overheat with the ac on. I believe I need to replace the high/low speed switch for the fan (pretty sure its the fan on the passengers side behind radiator) because when I turn on the ac, its running but I'm guessing just at low speed. I followed the wires to underneath where you add the power steering fluid. I need help in making sure im even in the right spot, and a pic of what this switch looks like would be greatly appreciated..

 

It's not a switch; there's a fan control module which runs all the fans by computer control. It's a square unit with connectors on one side and fins on the other, next to the driver's side intercooler. If there's a problem with it it will throw a fault code, so check the codes first.
Jim