I have an Arduino Uno drawing power from a 9V wall adapter plugged into its power jack. I have a 12V LED strip connected to the VIN pin of the Arduino (positive side to the VIN, negative to GND, of course) and the strip won't light up. I'm checking the voltage on the VIN and it's about 9V, which should be enough, because I'm testing the same strip with a 9V battery and it works OK.
I'm guessing that the issue is with the current, i.e the amperage output of the VIN pin, which is about 1A. In the specs of the LED strip it says it has input current of 400mA. Is this the issue? What should I do?