Hey.
I had the issue when my surface book battery died. I plugged in the charger wire and all i got was a flashing light. When i pressed the power button all i got was a black screen with a battery symbol in the middle.
After trying a few things. Like checking the plug socket and cleaning the points. I pressed the screen release button. It flashed green then immediately red. The book then started charging.
Hope this helps anyone having the same issue.