1)Switch off the console by holding down the power button, until the red light appears.
2)Place your finger on the disc eject button and keep your finger held on there.
3)Turn off the ps3 from the behind, by turning off the main switch that controls the power.
4)Then remove your finger from the eject button and turn back on again the PS3.
5)You should now hear the fan inside the PS3 spinning really fast and extremely loud. While its doing the cleaning process, any dust will be blown out of the air vents.
The PlayStation 3 fan test works on the following: 60gb, 40gb and 80gb consoles. (Not sure about the PS3 slim model).
Is the fan test bad? Can it damage the ps3 and is it safe?
No the fan test is not designed to damage the console in any shape or form. It is supposed to help the console cooling system, by removing dust that can cause overheating problems.