The "blue light of death" or "blinking blue light" or "pulsing blue light" is when you turn on your PS4 and the blue light turns on and blinks...actually it kind of pulses. There is not display on the TV (some TV's will just say "no signal" and it never goes to the white light. If you try to hold the power button long enough to get into safe mode it either won't do anything or it turns back off. You can't get to any menu or safe mode or anything like that because it won't let you get that far. This is the BLOD. There are many other problems people have with these game consoles but this describes what most people recognize as the blinking blue light or pulsing blue light.
The blinking blue light of death means the PS4 doesn’t enter the power on state indicated by the solid white light. Due to this there may not be any video or audio output to the television and could cause difficulties actually turning the console off. The problem might be attributed to TV compatibility, PS4 power supply, hard drive or hardware issues.
The symptoms associated with blinking blue lights issue: blue indicator light blinking no video/audio output to television console powering off after blinking blue