Try:
# Plugging into charger to get lights to turn on. (Should be white power light and battery lights)
# Hold down JBL+ and Volume Buttons for 10 seconds, unit should power off.
# Unplug power cord and press the power button, light should light up blue and issue resolved.
This fixed mine. Seemed to have helped a few others in the site as well. [br]
best of luck!