Antwort auf „diagnostics led meaning on macpro 2013”The Mac won’t come on without the housing. You will need a magnet. The 2 LEDs that come on when pressing the button only verify that it’s plugged into a power source and getting 12V. Remove the bottom cover, then you will be able to access all diagnostic LEDs. Photo shows what kind of magnet will work and where to hold it to power the Mac on without the housing.