Pilot light on 580 EX II not turning on at all

[bensonwu]

Hello all. I've had this unit for a little over a year, but I don't use it so frequently. Recently, I took the flash out and turned it on, but the pilot light wouldn't turn on at all. I could still configure the settings, but despite my efforts, the pilot light still wouldn't turn on? Any suggestions? 

[RobertTheFat]

Recharge the batteries.

[TCampbell]

The batteries do not directly power the flash itself. They charge an internal capacitor which is able to release its power in a surge.

If the batteries are low, they'll still power the unit so you see the LCD panel, but they won't have enough power to charge the capacitor and you won't get a pilot light (or you may eventually get one after a very long wait.)