I had problems with my 2 Discos with temperature rising during traffic. A simple test without removing anything that will prove signs that the fan is not working or dead.

1) Get a barbcue stick
2) Poke the stick through the grill and through the fan grill
3) Try turning the blade clockwise

If the blade do not turn with little effort, fan is dead.
Result: made my temperature stable during traffic.
Cheers!
gerry
I just replaced the fan today. But instead if removing the grill and unplugging and test to battery, the stick test will do some simple check.
See the stick bend and still the fan wont move. A sign that its frozen.
This is when the fan moves freely without much effort rurning it

 

But don't do this with your digit or you may end up 'picking ya nose with your toe'

 

All the time, liking your comments! Btw, or with a stick.