Had a problem today where my new Xbox 360 wireless controller wouldn’t connect. All four quadrant lights would blink on and off until I removed the batteries.
My fix was to push the connect button on the console and the one on the controller simultaneously. The connect button is the little one next to the left button on the back of the controller, next to the ‘(((‘ symbol. Find the same button on the front of the 360 console, then push them both at the same time, hold for 2 or 3 secs (until the lights start to “spin” on the controller), then release.
Hopefully it works for you.