Battery Status Lights
If the computer is connected to an electrical outlet, the battery light operates as follows:
Alternately blinking amber light and blue light — An unauthenticated or unsupported, non-Dell AC adapter is attached to your laptop.
Alternately blinking amber light with steady blue light — Temporary battery failure with AC adapter present.
Constantly blinking amber light — Fatal battery failure with AC adapter present.
Light off — Battery in full charge mode with AC adapter present.
Blue light on — Battery in charge mode with AC adapter present.
How about the Blue status light flashing constantly after closing lid with Laptop left on?